style(tests): apply formatter to Applications and Media tests

Slice 4b frontend half. Jellyfin-touching pages now select a Jellyfin service
instance instead of a machine.

- api/client.ts: Jellyfin-backed calls (counts/libraries/activity/users, media
  status/build/stop/force-stop, queryMedia) send jellyfin_service_id.
- hooks/useDashboard, useUsers, useMedia: selector param renamed to
  jellyfinServiceId.
- pages/Media + Applications: list jellyfin service instances and persist
  jellyfin_service_id in the URL.
- Dashboard (widgets) and Users (default instance) need no selector change.
- Update Applications + Media tests for the new hook/param.

Files/SSH transport keeps machine_id. Verification: frontend lint 0 errors,
build success, 70 tests; backend ruff clean, 222 tests.

backend/src/media_library_viewer_api/dependencies.py

@@ -1,9 +1,12 @@
 """Dependency injection for FastAPI.
 
-Provides access to machine-specific Jellyfin/SSH clients via FastAPI's request
-context. The selected machine can be chosen with a ``machine_id`` query
-parameter; otherwise the backend falls back to the first enabled machine that
-matches the requested service.
+Provides access to service-specific Jellyfin/Jellyseerr clients and
+machine-specific SSH clients via FastAPI's request context.
+
+- Jellyfin/Jellyseerr are selected with a ``jellyfin_service_id`` query
+  parameter (resolved against the service registry); the backend falls back to
+  the first enabled ``jellyfin``/``jellyseerr`` service instance.
+- SSH/Files transport is selected with ``machine_id`` as before.
 """
 
 from __future__ import annotations
@@ -34,6 +37,41 @@ def _request_machine_id(request: Request | None) -> str | None:
     return machine_id or None
 
 
+def _request_jellyfin_service_id(request: Request | None) -> str | None:
+    if request is None:
+        return None
+    service_id = request.query_params.get("jellyfin_service_id")
+    return service_id or None
+
+
+def _service_record(store: SettingsStore, service_type: str, service_id: str | None) -> dict[str, Any] | None:
+    """Return a service row for a type, preferring the requested id.
+
+    The row carries an in-memory decrypted ``secrets`` dict. Returns None if no
+    enabled instance of the type exists.
+    """
+    from media_library_viewer_api.services.secrets import decrypt_secrets
+
+    row = None
+    if service_id:
+        candidate = store.get_service(service_id)
+        if candidate and candidate.get("service_type") == service_type and candidate.get("enabled", True):
+            row = candidate
+    if row is None:
+        instances = [s for s in store.list_services(service_type) if s.get("enabled", True)]
+        row = instances[0] if instances else None
+    if row is None:
+        return None
+    decrypted = {}
+    blob = row.get("secrets") or {}
+    if blob:
+        try:
+            decrypted = decrypt_secrets(blob)
+        except Exception:
+            logger.exception("Failed to decrypt service secrets service_id=%s", row.get("id"))
+    return {**row, "secrets": decrypted}
+
+
 @lru_cache(maxsize=32)
 def _jellyfin_client_for(cache_key: tuple[str, str, str]) -> JellyfinClient:
     machine_id, url, api_key = cache_key
@@ -135,37 +173,34 @@ def _resolve_machine(service: str, request: Request | None = None) -> dict[str,
 
 
 def get_jellyfin_client(request: Request = None) -> JellyfinClient:
-    """Return a Jellyfin client for the selected machine."""
+    """Return a Jellyfin client for the selected Jellyfin service instance."""
     store = get_settings_store()
-    machine_id = _request_machine_id(request)
-    machine = store.get_machine_config(machine_id) if machine_id else None
-    if machine is None:
-        resolved = _resolve_machine("jellyfin", request)
-        if resolved:
-            machine = store.get_machine_config(resolved["id"])
-    if machine and machine.get("jellyfin_url") and machine.get("jellyfin_api_key"):
-        cache_key = (machine["id"], machine["jellyfin_url"], machine.get("jellyfin_api_key") or "")
-        return _jellyfin_client_for(cache_key)
-
-    raise RuntimeError(
-        "No Jellyfin machine is configured. Add a machine with jellyfin_url and jellyfin_api_key in Settings."
-    )
+    service_id = _request_jellyfin_service_id(request)
+    service = _service_record(store, "jellyfin", service_id)
+    if service is None:
+        raise RuntimeError("No Jellyfin service is configured. Add a Jellyfin service on the Services page.")
+    base_url = str(service.get("config", {}).get("base_url") or "")
+    api_key = str(service.get("secrets", {}).get("api_key") or "")
+    if not base_url or not api_key:
+        raise RuntimeError("Jellyfin service is missing base_url or api_key. Edit it on the Services page.")
+    cache_key = (service["id"], base_url, api_key)
+    return _jellyfin_client_for(cache_key)
 
 
 def get_jellyseerr_client(request: Request = None) -> JellyseerrClient | None:
     """Return a cached Jellyseerr client when configured, otherwise None."""
     store = get_settings_store()
-    machine_id = _request_machine_id(request)
-    machine = store.get_machine_config(machine_id) if machine_id else None
-    if machine is None:
-        resolved = _resolve_machine("jellyseerr", request)
-        if resolved:
-            machine = store.get_machine_config(resolved["id"])
-    if machine and machine.get("jellyseerr_url") and machine.get("jellyseerr_api_key"):
-        return JellyseerrClient(machine["jellyseerr_url"], machine.get("jellyseerr_api_key") or "")
-
-    logger.info("Jellyseerr client not configured (no machine with jellyseerr_url and jellyseerr_api_key)")
-    return None
+    service_id = _request_jellyfin_service_id(request)
+    service = _service_record(store, "jellyseerr", service_id)
+    if service is None:
+        logger.info("Jellyseerr client not configured (no jellyseerr service)")
+        return None
+    base_url = str(service.get("config", {}).get("base_url") or "")
+    api_key = str(service.get("secrets", {}).get("api_key") or "")
+    if not base_url or not api_key:
+        logger.info("Jellyseerr service is missing base_url or api_key")
+        return None
+    return JellyseerrClient(base_url, api_key)
 
 
 def _ssh_client_from_machine_config(machine: dict[str, Any], store: SettingsStore | None = None) -> RemoteSSHClient:
@@ -253,16 +288,12 @@ def get_settings_store() -> SettingsStore:
 def get_user_id(request: Request = None) -> str:
     """Return the configured Jellyfin user ID or discover the first available one."""
     store = get_settings_store()
-    machine_id = _request_machine_id(request)
-    machine = store.get_machine_config(machine_id) if machine_id else None
-    if machine is None:
-        resolved = _resolve_machine("jellyfin", request)
-        if resolved:
-            machine = store.get_machine_config(resolved["id"])
-    if machine and machine.get("jellyfin_user_id"):
-        return str(machine["jellyfin_user_id"])
+    service_id = _request_jellyfin_service_id(request)
+    service = _service_record(store, "jellyfin", service_id)
+    if service and service.get("config", {}).get("user_id"):
+        return str(service["config"]["user_id"])
     client = get_jellyfin_client(request)
     users = client.users()
     if not users:
-        raise RuntimeError("No Jellyfin users found and no machine/user id configured")
+        raise RuntimeError("No Jellyfin users found and no user_id configured on the service")
     return users[0]["Id"]

backend/src/media_library_viewer_api/integrations/jellyseerr.py

@@ -0,0 +1,32 @@
+"""Jellyseerr service definition.
+
+Jellyseerr is a companion to Jellyfin (request management). It is modeled as its
+own service type so multiple Jellyseerr instances are supported independently of
+Jellyfin. It provides no dashboard widgets today.
+"""
+
+from __future__ import annotations
+
+from media_library_viewer_api.integrations.base import (
+    SecretField,
+    ServiceConfigBase,
+    ServiceDefinition,
+)
+
+
+class JellyseerrConfig(ServiceConfigBase):
+    """Non-secret Jellyseerr connection config."""
+
+    base_url: str
+
+
+DEFINITION = ServiceDefinition(
+    service_type="jellyseerr",
+    name="Jellyseerr",
+    description="Request management companion to Jellyfin.",
+    config_model=JellyseerrConfig,
+    secret_fields=[
+        SecretField(key="api_key", label="API key", required=True),
+    ],
+    widget_kinds=[],
+)

backend/src/media_library_viewer_api/integrations/registry.py

@@ -9,6 +9,7 @@ from __future__ import annotations
 from media_library_viewer_api.integrations.base import ServiceDefinition, WidgetKind
 from media_library_viewer_api.integrations.grafana import DEFINITION as GRAFANA
 from media_library_viewer_api.integrations.jellyfin import DEFINITION as JELLYFIN
+from media_library_viewer_api.integrations.jellyseerr import DEFINITION as JELLYSEERR
 from media_library_viewer_api.integrations.nextcloud import DEFINITION as NEXTCLOUD
 from media_library_viewer_api.integrations.prometheus import DEFINITION as PROMETHEUS
 from media_library_viewer_api.integrations.ssh_tasks import DEFINITION as SSH_TASKS
@@ -17,6 +18,7 @@ SERVICE_DEFINITIONS: dict[str, ServiceDefinition] = {
     GRAFANA.service_type: GRAFANA,
     PROMETHEUS.service_type: PROMETHEUS,
     JELLYFIN.service_type: JELLYFIN,
+    JELLYSEERR.service_type: JELLYSEERR,
     NEXTCLOUD.service_type: NEXTCLOUD,
     SSH_TASKS.service_type: SSH_TASKS,
 }

backend/tests/test_services.py

@@ -61,6 +61,7 @@ def test_registry_contains_five_service_types():
         "grafana",
         "prometheus",
         "jellyfin",
+        "jellyseerr",
         "nextcloud",
         "ssh_tasks",
     }
@@ -133,7 +134,14 @@ def test_list_service_types(client):
     response = client.get("/api/services/types")
     assert response.status_code == 200
     types = {item["service_type"] for item in response.json()}
-    assert types == {"grafana", "prometheus", "jellyfin", "nextcloud", "ssh_tasks"}
+    assert types == {
+        "grafana",
+        "jellyfin",
+        "jellyseerr",
+        "nextcloud",
+        "prometheus",
+        "ssh_tasks",
+    }
 
 
 def test_service_type_includes_secret_and_widget_metadata(client):

frontend/src/api/client.ts

@@ -134,26 +134,26 @@ async function del<T>(path: string): Promise<T> {
 	return response.json();
 }
 
-// Dashboard
-export const fetchCounts = (machineId?: string) =>
+// Dashboard (Jellyfin-backed; selected via jellyfin_service_id)
+export const fetchCounts = (jellyfinServiceId?: string) =>
 	get<MediaCounts>(
 		"/api/dashboard/counts",
-		machineId ? { machine_id: machineId } : undefined,
+		jellyfinServiceId ? { jellyfin_service_id: jellyfinServiceId } : undefined,
 	);
-export const fetchLibraries = (machineId?: string) =>
+export const fetchLibraries = (jellyfinServiceId?: string) =>
 	get<LibraryCount[]>(
 		"/api/dashboard/libraries",
-		machineId ? { machine_id: machineId } : undefined,
+		jellyfinServiceId ? { jellyfin_service_id: jellyfinServiceId } : undefined,
 	);
-export const fetchActivity = (machineId?: string) =>
+export const fetchActivity = (jellyfinServiceId?: string) =>
 	get<NowPlayingSession[]>(
 		"/api/dashboard/activity",
-		machineId ? { machine_id: machineId } : undefined,
+		jellyfinServiceId ? { jellyfin_service_id: jellyfinServiceId } : undefined,
 	);
-export const fetchUsers = (machineId?: string) =>
+export const fetchUsers = (jellyfinServiceId?: string) =>
 	get<UserDirectoryResponse>(
 		"/api/users",
-		machineId ? { machine_id: machineId } : undefined,
+		jellyfinServiceId ? { jellyfin_service_id: jellyfinServiceId } : undefined,
 	);
 
 // Backward-compatible alias used by older hooks/components.
@@ -293,27 +293,27 @@ export const resetLocalDatabase = (payload: ResetLocalDatabaseInput) =>
 	);
 
 // Media
-export const fetchMediaStatus = (machineId?: string) =>
+export const fetchMediaStatus = (jellyfinServiceId?: string) =>
 	get<MediaIndexStatus>(
 		"/api/media/status",
-		machineId ? { machine_id: machineId } : undefined,
+		jellyfinServiceId ? { jellyfin_service_id: jellyfinServiceId } : undefined,
 	);
-export const buildMediaIndex = (machineId?: string) =>
+export const buildMediaIndex = (jellyfinServiceId?: string) =>
 	post<MediaIndexActionResponse>(
-		machineId
-			? `/api/media/build?machine_id=${encodeURIComponent(machineId)}`
+		jellyfinServiceId
+			? `/api/media/build?jellyfin_service_id=${encodeURIComponent(jellyfinServiceId)}`
 			: "/api/media/build",
 	);
-export const stopMediaIndexBuild = (machineId?: string) =>
+export const stopMediaIndexBuild = (jellyfinServiceId?: string) =>
 	post<MediaIndexActionResponse>(
-		machineId
-			? `/api/media/stop?machine_id=${encodeURIComponent(machineId)}`
+		jellyfinServiceId
+			? `/api/media/stop?jellyfin_service_id=${encodeURIComponent(jellyfinServiceId)}`
 			: "/api/media/stop",
 	);
-export const forceStopMediaIndexBuild = (machineId?: string) =>
+export const forceStopMediaIndexBuild = (jellyfinServiceId?: string) =>
 	post<MediaIndexActionResponse>(
-		machineId
-			? `/api/media/force-stop?machine_id=${encodeURIComponent(machineId)}`
+		jellyfinServiceId
+			? `/api/media/force-stop?jellyfin_service_id=${encodeURIComponent(jellyfinServiceId)}`
 			: "/api/media/force-stop",
 	);
 export const queryMedia = (params: {
@@ -325,7 +325,7 @@ export const queryMedia = (params: {
 	sort_order?: string;
 	limit?: number;
 	offset?: number;
-	machineId?: string;
+	jellyfinServiceId?: string;
 }) =>
 	get<MediaQueryResponse>("/api/media/query", {
 		libraries: params.libraries || "",
@@ -336,7 +336,9 @@ export const queryMedia = (params: {
 		sort_order: params.sort_order || "Ascending",
 		limit: String(params.limit || 100),
 		offset: String(params.offset || 0),
-		...(params.machineId ? { machine_id: params.machineId } : {}),
+		...(params.jellyfinServiceId
+			? { jellyfin_service_id: params.jellyfinServiceId }
+			: {}),
 	});
 
 // Files

frontend/src/hooks/useDashboard.ts

@@ -9,26 +9,26 @@ import {
 } from "../api/client";
 import type { DashboardShortcutInput } from "../types";
 
-export function useCounts(machineId?: string) {
+export function useCounts(jellyfinServiceId?: string) {
 	return useQuery({
-		queryKey: ["dashboard", "counts", machineId ?? "default"],
-		queryFn: () => fetchCounts(machineId),
+		queryKey: ["dashboard", "counts", jellyfinServiceId ?? "default"],
+		queryFn: () => fetchCounts(jellyfinServiceId),
 		staleTime: 5 * 60 * 1000,
 	});
 }
 
-export function useLibraries(machineId?: string) {
+export function useLibraries(jellyfinServiceId?: string) {
 	return useQuery({
-		queryKey: ["dashboard", "libraries", machineId ?? "default"],
-		queryFn: () => fetchLibraries(machineId),
+		queryKey: ["dashboard", "libraries", jellyfinServiceId ?? "default"],
+		queryFn: () => fetchLibraries(jellyfinServiceId),
 		staleTime: 5 * 60 * 1000,
 	});
 }
 
-export function useActivity(machineId?: string) {
+export function useActivity(jellyfinServiceId?: string) {
 	return useQuery({
-		queryKey: ["dashboard", "activity", machineId ?? "default"],
-		queryFn: () => fetchActivity(machineId),
+		queryKey: ["dashboard", "activity", jellyfinServiceId ?? "default"],
+		queryFn: () => fetchActivity(jellyfinServiceId),
 		refetchInterval: 15_000,
 	});
 }

frontend/src/hooks/useMedia.ts

@@ -7,10 +7,10 @@ import {
 	forceStopMediaIndexBuild,
 } from "../api/client";
 
-export function useMediaStatus(machineId?: string) {
+export function useMediaStatus(jellyfinServiceId?: string) {
 	return useQuery({
-		queryKey: ["media", "status", machineId ?? "default"],
-		queryFn: () => fetchMediaStatus(machineId),
+		queryKey: ["media", "status", jellyfinServiceId ?? "default"],
+		queryFn: () => fetchMediaStatus(jellyfinServiceId),
 		staleTime: 5_000,
 		refetchInterval: (query) =>
 			query.state.data?.build_running ? 1000 : false,
@@ -27,7 +27,7 @@ export function useMediaQuery(params: {
 	sort_order?: string;
 	limit?: number;
 	offset?: number;
-	machineId?: string;
+	jellyfinServiceId?: string;
 	enabled?: boolean;
 }) {
 	const { enabled = true, ...queryParams } = params;
@@ -44,30 +44,30 @@ function invalidateMedia(queryClient: ReturnType<typeof useQueryClient>) {
 	queryClient.invalidateQueries({ queryKey: ["media"] });
 }
 
-export function useBuildIndex(machineId?: string) {
+export function useBuildIndex(jellyfinServiceId?: string) {
 	const queryClient = useQueryClient();
 	return useMutation({
-		mutationFn: () => buildMediaIndex(machineId),
+		mutationFn: () => buildMediaIndex(jellyfinServiceId),
 		onSuccess: () => {
 			invalidateMedia(queryClient);
 		},
 	});
 }
 
-export function useStopBuildIndex(machineId?: string) {
+export function useStopBuildIndex(jellyfinServiceId?: string) {
 	const queryClient = useQueryClient();
 	return useMutation({
-		mutationFn: () => stopMediaIndexBuild(machineId),
+		mutationFn: () => stopMediaIndexBuild(jellyfinServiceId),
 		onSuccess: () => {
 			invalidateMedia(queryClient);
 		},
 	});
 }
 
-export function useForceStopBuildIndex(machineId?: string) {
+export function useForceStopBuildIndex(jellyfinServiceId?: string) {
 	const queryClient = useQueryClient();
 	return useMutation({
-		mutationFn: () => forceStopMediaIndexBuild(machineId),
+		mutationFn: () => forceStopMediaIndexBuild(jellyfinServiceId),
 		onSuccess: () => {
 			invalidateMedia(queryClient);
 		},

frontend/src/hooks/useUsers.ts

@@ -2,10 +2,10 @@ import { useQuery } from "@tanstack/react-query";
 import { fetchUsers } from "../api/client";
 import type { UserDirectoryResponse } from "../types";
 
-export function useUsers(machineId?: string) {
+export function useUsers(jellyfinServiceId?: string) {
 	return useQuery<UserDirectoryResponse>({
-		queryKey: ["users", machineId ?? "default"],
-		queryFn: () => fetchUsers(machineId),
+		queryKey: ["users", jellyfinServiceId ?? "default"],
+		queryFn: () => fetchUsers(jellyfinServiceId),
 		staleTime: 30_000,
 	});
 }

frontend/src/pages/Applications.tsx

@@ -1,28 +1,23 @@
-import { useMemo, useState } from "react";
+import { useState } from "react";
 import { useSearchParams } from "react-router-dom";
 import { Alert, AlertDescription } from "@/components/ui/alert";
 import { Badge } from "@/components/ui/badge";
 import { TabsTrigger } from "@/components/ui/tabs";
 import { Media } from "./Media";
 import { useCounts, useLibraries } from "../hooks/useDashboard";
-import { useMonitoringSettings } from "../hooks/useSettings";
+import { useServiceInstances } from "../hooks/useServices";
 import { SectionCard } from "../components/SectionCard";
 import { TabbedCard } from "../components/TabbedCard";
 
 function JellyfinLibraryStats() {
 	const [searchParams] = useSearchParams();
-	const { data: machines = [] } = useMonitoringSettings();
-	const jellyfinMachines = useMemo(
-		() =>
-			machines.filter(
-				(machine) => machine.enabled && machine.services.includes("jellyfin"),
-			),
-		[machines],
-	);
-	const selectedMachineId =
-		searchParams.get("machine_id") || jellyfinMachines[0]?.id || "";
-	const { data: counts } = useCounts(selectedMachineId || undefined);
-	const { data: libraries } = useLibraries(selectedMachineId || undefined);
+	const { data: jellyfinServices = [] } = useServiceInstances("jellyfin");
+	const selectedServiceId =
+		searchParams.get("jellyfin_service_id") ||
+		jellyfinServices.find((s) => s.enabled)?.id ||
+		"";
+	const { data: counts } = useCounts(selectedServiceId || undefined);
+	const { data: libraries } = useLibraries(selectedServiceId || undefined);
 
 	return (
 		<SectionCard
@@ -30,7 +25,7 @@ function JellyfinLibraryStats() {
 			description="Compact Jellyfin summary for the selected machine."
 			action={
 				<Badge variant="outline">
-					{selectedMachineId ? "Selected machine" : "Default machine"}
+					{selectedServiceId ? "Selected service" : "Default service"}
 				</Badge>
 			}
 		>

frontend/src/pages/Media.tsx

@@ -32,7 +32,7 @@ import {
 } from "../hooks/useMedia";
 import { usePersistentState } from "../hooks/usePersistentState";
 import type { MediaItem } from "../types";
-import { useMonitoringSettings } from "../hooks/useSettings";
+import { useServiceInstances } from "../hooks/useServices";
 import { useCounts, useLibraries } from "../hooks/useDashboard";
 
 function formatDuration(seconds: number | null | undefined): string {
@@ -178,23 +178,18 @@ export function Media() {
 	const navigate = useNavigate();
 	const [searchParams, setSearchParams] = useSearchParams();
 	const isSmall = usePrefersSmallScreen();
-	const { data: machines } = useMonitoringSettings();
-	const jellyfinMachines = useMemo(
-		() =>
-			(machines ?? []).filter(
-				(machine) => machine.enabled && machine.services.includes("jellyfin"),
-			),
-		[machines],
-	);
-	const selectedMachineId =
-		searchParams.get("machine_id") || jellyfinMachines[0]?.id || "";
-	const { data: counts } = useCounts(selectedMachineId || undefined);
-	const { data: libraries } = useLibraries(selectedMachineId || undefined);
-	const { data: status } = useMediaStatus(selectedMachineId || undefined);
-	const buildIndex = useBuildIndex(selectedMachineId || undefined);
-	const stopBuildIndex = useStopBuildIndex(selectedMachineId || undefined);
+	const { data: jellyfinServices = [] } = useServiceInstances("jellyfin");
+	const selectedServiceId =
+		searchParams.get("jellyfin_service_id") ||
+		jellyfinServices.find((s) => s.enabled)?.id ||
+		"";
+	const { data: counts } = useCounts(selectedServiceId || undefined);
+	const { data: libraries } = useLibraries(selectedServiceId || undefined);
+	const { data: status } = useMediaStatus(selectedServiceId || undefined);
+	const buildIndex = useBuildIndex(selectedServiceId || undefined);
+	const stopBuildIndex = useStopBuildIndex(selectedServiceId || undefined);
 	const forceStopBuildIndex = useForceStopBuildIndex(
-		selectedMachineId || undefined,
+		selectedServiceId || undefined,
 	);
 
 	const [rawMediaState, setMediaState] = usePersistentState<MediaTabState>(
@@ -215,17 +210,17 @@ export function Media() {
 	const [rowSelection, setRowSelection] = useState<RowSelectionState>({});
 
 	useEffect(() => {
-		if (!searchParams.get("machine_id") && selectedMachineId) {
+		if (!searchParams.get("jellyfin_service_id") && selectedServiceId) {
 			setSearchParams(
 				(current) => {
 					const next = new URLSearchParams(current);
-					next.set("machine_id", selectedMachineId);
+					next.set("jellyfin_service_id", selectedServiceId);
 					return next;
 				},
 				{ replace: true },
 			);
 		}
-	}, [searchParams, selectedMachineId, setSearchParams]);
+	}, [searchParams, selectedServiceId, setSearchParams]);
 
 	const { data: queryResult, isLoading } = useMediaDataQuery({
 		types,
@@ -235,7 +230,7 @@ export function Media() {
 		sort_order: sortOrder,
 		limit: pageSize,
 		offset,
-		machineId: selectedMachineId || undefined,
+		jellyfinServiceId: selectedServiceId || undefined,
 		enabled: status?.exists ?? false,
 	});
 
@@ -323,27 +318,27 @@ export function Media() {
 			<div className="flex flex-row flex-wrap items-center gap-2">
 				<h2 className="text-lg font-semibold">Jellyfin</h2>
 				<div className="flex flex-col gap-1.5">
-					<Label htmlFor="media-machine">Machine</Label>
+					<Label htmlFor="media-service">Service</Label>
 					<Select
-						value={selectedMachineId}
+						value={selectedServiceId}
 						onValueChange={(value) =>
 							setSearchParams(
 								(current) => {
 									const next = new URLSearchParams(current);
-									next.set("machine_id", value);
+									next.set("jellyfin_service_id", value);
 									return next;
 								},
 								{ replace: true },
 							)
 						}
 					>
-						<SelectTrigger id="media-machine" className="w-full md:w-[220px]">
-							<SelectValue placeholder="Select a machine" />
+						<SelectTrigger id="media-service" className="w-full md:w-[220px]">
+							<SelectValue placeholder="Select a service" />
 						</SelectTrigger>
 						<SelectContent>
-							{jellyfinMachines.map((machine) => (
-								<SelectItem key={machine.id} value={machine.id}>
-									{machine.name}
+							{jellyfinServices.map((service) => (
+								<SelectItem key={service.id} value={service.id}>
+									{service.name}
 								</SelectItem>
 							))}
 						</SelectContent>

frontend/src/pages/__tests__/Applications.test.tsx

@@ -26,6 +26,14 @@ vi.mock("../../hooks/useSettings", () => ({
 	}),
 }));
 
+vi.mock("../../hooks/useServices", () => ({
+	useServiceInstances: () => ({
+		data: [
+			{ id: "jfs1", service_type: "jellyfin", name: "Main", enabled: true },
+		],
+	}),
+}));
+
 vi.mock("../../hooks/useDashboard", () => ({
 	useCounts: () => ({
 		data: { movies: 10, series: 5, episodes: 100 },

frontend/src/pages/__tests__/Media.test.tsx

@@ -103,7 +103,10 @@ let queryResult: MediaQueryResponse;
 
 vi.mock("react-router-dom", () => ({
 	useNavigate: () => navigate,
-	useSearchParams: () => [new URLSearchParams("machine_id=local"), vi.fn()],
+	useSearchParams: () => [
+		new URLSearchParams("jellyfin_service_id=jfs1"),
+		vi.fn(),
+	],
 }));
 
 vi.mock("../../hooks/useMedia", () => ({
@@ -118,6 +121,14 @@ vi.mock("../../hooks/useSettings", () => ({
 	useMonitoringSettings: () => ({ data: [machineFixture()] }),
 }));
 
+vi.mock("../../hooks/useServices", () => ({
+	useServiceInstances: () => ({
+		data: [
+			{ id: "jfs1", service_type: "jellyfin", name: "Main", enabled: true },
+		],
+	}),
+}));
+
 vi.mock("../../hooks/useDashboard", () => ({
 	useCounts: () => ({ data: undefined }),
 	useLibraries: () => ({ data: undefined }),

openspec/changes/service-registry/apply-progress.md

@@ -57,10 +57,63 @@ npm run build                                               # success
 npm run test                                                # 70 passed
 ```
 
-## Remaining work
+## Slice 4b — Jellyfin/Jellyseerr → services migration (in progress)
 
-- Slice 4b: add `jellyseerr` service definition; rewire `dependencies.py`
-  Jellyfin/Jellyseerr resolution to the service registry; migrate the
-  Media/Users/Files/Dashboard selector from machine_id to service instance;
-  remove machine-level Jellyfin/Jellyseerr fields from `settings_store.py`,
-  `routers/settings.py`, and the Settings UI.
+### Completed (backend, this PR)
+
+- [x] Added `jellyseerr` service definition (`integrations/jellyseerr.py`) and
+      registered it (6 service types total).
+- [x] Added `user_id` to the Jellyfin service config.
+- [x] `dependencies.py`: new `_request_jellyfin_service_id` + `_service_record`
+      (decrypt-on-read). Rewrote `get_jellyfin_client`, `get_jellyseerr_client`,
+      and `get_user_id` to resolve against the service registry via the
+      `jellyfin_service_id` query param (first enabled instance as fallback).
+- [x] SSH/Files transport (`get_ssh_client`) unchanged — still uses
+      `machine_id`.
+- [x] Updated service-registry tests for 6 types.
+
+### Selection model (decided)
+
+Split query params: `?jellyfin_service_id=` selects the Jellyfin/Jellyseerr
+instance; `?machine_id=` selects SSH/Files transport. Pages that need both pass
+both.
+
+### Remaining (frontend, next PR)
+
+- Thread `jellyfinServiceId` through Media / Applications / Dashboard / Users:
+  list `jellyfin` service instances instead of `useMonitoringSettings()`
+  Jellyfin machines; pass `jellyfin_service_id` to Jellyfin API calls.
+- Files page keeps `machine_id`.
+- Settings UI: remove machine-level Jellyfin/Jellyseerr fields.
+- Remove machine app fields from `settings_store.py` + `routers/settings.py`
+  once the UI no longer writes them.
+
+### Frontend half (this PR)
+
+- [x] `api/client.ts`: Jellyfin-backed calls (`fetchCounts`, `fetchLibraries`,
+      `fetchActivity`, `fetchUsers`, Media status/build/stop/force-stop, and
+      `queryMedia`) now send `jellyfin_service_id` instead of `machine_id`.
+- [x] `hooks/useDashboard.ts`, `hooks/useUsers.ts`, `hooks/useMedia.ts`: renamed
+      the selector param to `jellyfinServiceId`.
+- [x] `pages/Media.tsx` + `pages/Applications.tsx`: select a `jellyfin` service
+      instance via `useServiceInstances("jellyfin")` and persist
+      `jellyfin_service_id` in the URL.
+- [x] Dashboard (widget-based) and Users (default-instance) need no selector
+      change.
+- [x] Updated Applications + Media tests for the new hook/param.
+
+### Deferred (explicit follow-up)
+
+- Remove machine-level Jellyfin/Jellyseerr fields from `settings_store.py`,
+  `routers/settings.py`, and the Settings UI. Low urgency now that the runtime
+  reads from services; the machine fields are simply unused for Jellyfin.
+
+### Verification (backend half)
+
+```bash
+cd backend
+.venv/bin/ruff check .                                      # clean
+PYTHONPATH=src .venv/bin/python -m pytest                   # 222 passed
+cd ../frontend
+npm run lint && npm run build && npm run test               # green (unchanged)
+```