feat(widgets): add unit/scale config to chart widget kinds

Graph widgets need consistent value scaling (kB/MB/GB, kbps/Mbps, …). Add
shared `unit` (none/bytes/bytes_per_sec/bits_per_sec/bits/percent/seconds) and
`scale` (auto/k/m/g/t) enum fields to:

- PrometheusChartWidgetConfig (alongside promql/window)
- new QbittorrentSpeedWidgetConfig — the speed widget previously had NO config
  options at all; totals/active keep their empty config.

Declared as Pydantic Literal enums so the widget-kind JSON schema exposes
`enum`, which the frontend config dialog renders as a dropdown. The data
sources are unchanged (raw values); scaling is a display concern handled
client-side. qBittorrent speed defaults to bytes/sec.

Test: chart widget kinds expose the shared unit/scale enums; speed defaults to
bytes_per_sec; totals/active stay option-less. 389/389 backend tests pass.

backend/src/media_library_viewer_api/integrations/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: backend/src/media_library_viewer_api/integrations
 
 ## role
-Provides a plugin-based integration layer connecting the media library viewer API to various external services (Alertmanager, Authentik, Jellyfin, Prometheus, qBittorrent, etc.) via a centralized registry.
+Provides pluggable external service integrations (Alertmanager, Jellyfin, Nextcloud, Prometheus, qBittorrent, Authentik, Backups, SSH) with standardized config schemas, widgets, connection testing, and a central registry for discovery.
 ## parent
 index: backend/src/media_library_viewer_api/.pi-map.index.md
 map: backend/src/media_library_viewer_api/.pi-map.md

backend/src/media_library_viewer_api/integrations/.pi-map.md

@@ -4,7 +4,7 @@ dir: backend/src/media_library_viewer_api/integrations
 index: backend/src/media_library_viewer_api/integrations/.pi-map.index.md
 
 ## role
-Provides a plugin-based integration layer connecting the media library viewer API to various external services (Alertmanager, Authentik, Jellyfin, Prometheus, qBittorrent, etc.) via a centralized registry.
+Provides pluggable external service integrations (Alertmanager, Jellyfin, Nextcloud, Prometheus, qBittorrent, Authentik, Backups, SSH) with standardized config schemas, widgets, connection testing, and a central registry for discovery.
 ## files
 - __init__.py | Defines a closed registry module for service integrations.
 - alertmanager.py | Defines a service integration for Prometheus Alertmanager, providing configuration models, connection testing, alert summarization, and widget definitions for displaying active alerts. | exp: class:AlertmanagerConfig, class:AlertmanagerAlertsWidgetConfig, func:summarize_alerts(alerts: list[dict[str, Any]], severity_filter) → dict[str, Any], call:alert.get, call:labels.get, call:by_severity.get, call:open_alerts.append, call:annotations.get, call:open_alerts.sort, call:len, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str(config.get("base_url") or "").rstrip, call:config.get, call:int, call:secrets.get, call:requests.get, call:resp.raise_for_status, call:resp.json, call:payload.get("versionInfo", {}).get, call:TestResult, call:translate_connection_error | dep: typing, requests, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store
@@ -13,14 +13,14 @@ Provides a plugin-based integration layer connecting the media library viewer AP
 - base.py | Provides base classes and utility functions for defining external service integrations, including config schemas, secrets, widgets, and connection error translation. | exp: class:ServiceConfigBase, class:WidgetConfigBase, class:SecretField, class:WidgetKind, class:TestResult, class:ServiceDefinition, method:widget_kind(self, kind: str) → WidgetKind | None, func:_validate_service_base_url(value: Any) → str, call:isinstance, call:value.strip, call:text.lower, call:lowered.startswith, raise:ValueError, func:widget_kind(kind: str, name: str, description: str, model_cls: type[WidgetConfigBase], default_config, refresh_interval_ms) → WidgetKind, call:model_cls.model_json_schema, call:schema.pop, call:WidgetKind, call:dict, func:validate_config(model_cls: type[BaseModel], config: dict[str, Any] | None) → dict[str, Any], call:model_cls.model_validate, call:instance.model_dump, func:translate_connection_error(exc: Exception, context) → TestResult, call:str, call:message.lower, call:isinstance, call:TestResult | dep: asyncio, dataclasses, typing, requests, pydantic, media_library_viewer_api.services.settings_store
 - jellyfin.py | Defines the Jellyfin media server service integration, including connection testing, configuration models, and widget definitions for activity monitoring. | exp: class:JellyfinConfig, class:JellyfinActivityWidgetConfig, class:JellyfinNowPlayingWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str, call:config.get, call:secrets.get, call:int, call:JellyfinClient, call:client.users, call:TestResult, call:len, call:translate_connection_error | dep: typing, media_library_viewer_api.clients.jellyfin, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store, media_library_viewer_api.clients.jellyfin.JellyfinClient, media_library_viewer_api.services.settings_store.SettingsStore
 - nextcloud.py | Defines a Nextcloud service integration with connection testing and configuration for a media library viewer API. | exp: class:NextcloudConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str(config.get("base_url") or "").rstrip, call:config.get, call:requests.get, call:resp.raise_for_status, call:resp.json, call:payload.get, call:TestResult, call:translate_connection_error | dep: typing, requests, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store
-- prometheus.py | Defines a Prometheus service integration that queries metrics through a Grafana gateway and provides configuration for metric, chart, gauge, and mean widgets. | exp: class:PrometheusConfig, class:PrometheusMetricWidgetConfig, class:PrometheusChartWidgetConfig, class:PrometheusGaugeWidgetConfig, class:PrometheusMeanWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str(config.get("grafana_url") or "").rstrip, call:config.get, call:secrets.get, call:int, call:TestResult, call:requests.post, call:resp.raise_for_status, call:translate_connection_error | dep: typing, requests, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store
-- qbittorrent.py | Defines the qBittorrent service integration including config models, connection testing, and widget definitions for displaying torrent activity and speeds. | exp: class:QbittorrentConfig, class:QbittorrentWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:config.get, call:secrets.get, call:int, call:QbittorrentClient, call:client.maindata, call:data.get("server_state", {}).get, call:TestResult, call:str(exc).lower, call:translate_connection_error | dep: typing, media_library_viewer_api.clients.qbittorrent, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store, media_library_viewer_api.clients.qbittorrent.QbittorrentClient, media_library_viewer_api.services.settings_store.SettingsStore
+- prometheus.py | Defines the Prometheus service integration for a media library viewer API, including connection testing via a Grafana gateway and configuration models for metric, chart, gauge, and mean widgets. | exp: class:PrometheusConfig, class:PrometheusMetricWidgetConfig, class:PrometheusChartWidgetConfig, class:PrometheusGaugeWidgetConfig, class:PrometheusMeanWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str(config.get("grafana_url") or "").rstrip, call:config.get, call:secrets.get, call:int, call:TestResult, call:requests.post, call:resp.raise_for_status, call:translate_connection_error | dep: typing, requests, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store
+- qbittorrent.py | Defines the qBittorrent service integration, including connection config, secret fields, three widget kinds (totals, active, speed), and a connection test function. | exp: class:QbittorrentConfig, class:QbittorrentWidgetConfig, class:QbittorrentSpeedWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:config.get, call:secrets.get, call:int, call:QbittorrentClient, call:client.maindata, call:data.get("server_state", {}).get, call:TestResult, call:str(exc).lower, call:translate_connection_error | dep: typing, media_library_viewer_api.clients.qbittorrent, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store, media_library_viewer_api.clients.qbittorrent.QbittorrentClient, media_library_viewer_api.services.settings_store.SettingsStore
 - registry.py | Maintains a closed registry of service definitions and provides lookup functions to query available services, their types, and widget kinds. | exp: func:list_service_types() → list[str], call:sorted, func:get_service_definition(service_type: str) → ServiceDefinition | None, call:SERVICE_DEFINITIONS.get, func:get_widget_kind(service_type: str, widget_kind: str) → WidgetKind | None, call:get_service_definition, call:definition.widget_kind, func:require_service_definition(service_type: str) → ServiceDefinition, call:get_service_definition, raise:ValueError | dep: media_library_viewer_api.integrations.alertmanager, media_library_viewer_api.integrations.authentik, media_library_viewer_api.integrations.backups, media_library_viewer_api.integrations.base, media_library_viewer_api.integrations.jellyfin, media_library_viewer_api.integrations.nextcloud, media_library_viewer_api.integrations.prometheus, media_library_viewer_api.integrations.qbittorrent, media_library_viewer_api.integrations.ssh_tasks
 - ssh_tasks.py | Defines a service plugin that runs reusable saved tasks over SSH by managing connection configuration, secrets, and connection testing. | exp: class:SshTasksConfig, class:SshTaskOutputWidgetConfig, func:test_connection(config: dict[str, Any], secrets: dict[str, str], store: SettingsStore) → TestResult, call:str(config.get("host") or "").strip, call:config.get, call:int, call:ServiceRecord, call:build_ssh_client, call:client.connect, call:str(exc).lower, call:TestResult, call:translate_connection_error, call:client.close | dep: typing, media_library_viewer_api.integrations.base, media_library_viewer_api.services.settings_store, media_library_viewer_api.services.task_runner, media_library_viewer_api.widgets.sources
 ## arch
-Registry pattern with a shared base class defining config schemas, secrets, widgets, and connection-testing contracts; each integration is a self-contained module registered in a closed registry for runtime discovery.
+Plugin/registry pattern with abstract base classes defining config models, secrets, widgets, and connection tests; each integration is a self-contained module registered in a closed registry for lookup and dynamic loading.
 ## tags
-config, connection, widget, media_library_viewer_api, service, error, integrations, call:str
+config, connection, widget, media_library_viewer_api, service, error, integrations, test
 ## symbols
 - AlertmanagerConfig
 - AlertmanagerAlertsWidgetConfig

backend/src/media_library_viewer_api/integrations/prometheus.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 import requests
 
@@ -87,6 +87,18 @@ class PrometheusChartWidgetConfig(WidgetConfigBase):
 
     promql: str
     window: str = "1h"  # one of 1h / 6h / 24h / 7d (see WINDOW_PRESETS)
+    # Display scaling for the Y axis + tooltip. "none" shows raw values; the
+    # others auto/force a decimal-prefix unit (kB/MB/GB, kbps/Mbps, etc.).
+    unit: Literal[
+        "none",
+        "bytes",
+        "bytes_per_sec",
+        "bits_per_sec",
+        "bits",
+        "percent",
+        "seconds",
+    ] = "none"
+    scale: Literal["auto", "k", "m", "g", "t"] = "auto"
 
 
 class PrometheusGaugeWidgetConfig(WidgetConfigBase):

backend/src/media_library_viewer_api/integrations/qbittorrent.py

@@ -7,7 +7,7 @@ password), and three widget kinds (totals, active, speed). Models on
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 from media_library_viewer_api.clients.qbittorrent import QbittorrentClient
 from media_library_viewer_api.integrations.base import (
@@ -59,11 +59,26 @@ class QbittorrentConfig(ServiceConfigBase):
 
 
 class QbittorrentWidgetConfig(WidgetConfigBase):
-    """Per-widget config (empty — all three kinds derive from the service connection)."""
+    """Per-widget config for totals/active (empty — derived from the service connection)."""
 
     pass
 
 
+class QbittorrentSpeedWidgetConfig(WidgetConfigBase):
+    """Speed chart config. The source returns raw bytes/sec; the frontend scales."""
+
+    unit: Literal[
+        "none",
+        "bytes",
+        "bytes_per_sec",
+        "bits_per_sec",
+        "bits",
+        "percent",
+        "seconds",
+    ] = "bytes_per_sec"
+    scale: Literal["auto", "k", "m", "g", "t"] = "auto"
+
+
 DEFINITION = ServiceDefinition(
     service_type="qbittorrent",
     name="qBittorrent",
@@ -94,8 +109,8 @@ DEFINITION = ServiceDefinition(
             kind="speed",
             name="Speed chart",
             description="Live download/upload speed over a short window.",
-            model_cls=QbittorrentWidgetConfig,
-            default_config={},
+            model_cls=QbittorrentSpeedWidgetConfig,
+            default_config={"unit": "bytes_per_sec", "scale": "auto"},
             refresh_interval_ms=5_000,
         ),
     ],

backend/tests/test_services.py

@@ -114,6 +114,29 @@ def test_widget_kind_lookup():
     assert get_widget_kind("unknown", "metric") is None
 
 
+def test_chart_widget_kinds_expose_unit_and_scale_options():
+    """Graph widgets share unit/scale options so axes/tooltips can be scaled."""
+    units = ["none", "bytes", "bytes_per_sec", "bits_per_sec", "bits", "percent", "seconds"]
+    scales = ["auto", "k", "m", "g", "t"]
+
+    prom_chart = get_widget_kind("prometheus", "chart")
+    assert prom_chart is not None
+    prom_props = prom_chart.config_schema["properties"]
+    assert prom_props["unit"]["enum"] == units
+    assert prom_props["scale"]["enum"] == scales
+
+    qbit_speed = get_widget_kind("qbittorrent", "speed")
+    assert qbit_speed is not None
+    qbit_props = qbit_speed.config_schema["properties"]
+    assert qbit_props["unit"]["enum"] == units
+    assert qbit_props["scale"]["enum"] == scales
+    # qBittorrent speed data is bytes/sec by default.
+    assert qbit_speed.default_config["unit"] == "bytes_per_sec"
+    # totals/active are not graphs and stay option-less.
+    assert "unit" not in get_widget_kind("qbittorrent", "totals").config_schema["properties"]
+    assert "unit" not in get_widget_kind("qbittorrent", "active").config_schema["properties"]
+
+
 def test_service_config_schema_is_json_schema():
     schema = get_service_definition("prometheus").config_schema
     assert schema["type"] == "object"