feat: implement tool-session progress panel and live list updates

- Add SessionOperationsContext + SessionProgressPanel for global,
  non-blocking lifecycle progress (create/start/stop/restart/delete/
  recreate-tunnel) driven by SSE events.
- Promote SessionsContext to authoritative shared session state with
  refresh, addOrUpdateSession, and removeSession helpers.
- Wire AppShell, DashboardPage, SessionsPage, useInstanceActions,
  ToolStarter, and InstanceList into shared state so lists update
  immediately after create/delete without manual refresh.
- Remove legacy blocking overlays from CreateSessionForm, SessionCard,
  and InstanceList; keep disabled states and inline spinners only.
- Update DashboardPage tests to wrap with SessionsProvider and
  SessionOperationsProvider.
- Add .cache/ to .gitignore.

Quality gates: npm run typecheck, npm run lint, npm test -- --run
(82 passed).

apps/web/src/hooks/use-instance-actions.ts

@@ -7,6 +7,8 @@ import {
 	renameInstance,
 } from "../api/sessions";
 import type { Session } from "../api/sessions";
+import { useSessions } from "../state/sessions";
+import { useSessionOperations } from "../state/session-operations";
 
 interface UseInstanceActionsOptions {
 	onRefresh: () => Promise<void>;
@@ -30,6 +32,8 @@ export function useInstanceActions(
 	options: UseInstanceActionsOptions,
 ): UseInstanceActionsReturn {
 	const { onRefresh } = options;
+	const { removeSession } = useSessions();
+	const { startOperation, completeOperation } = useSessionOperations();
 	const [loadingSessionId, setLoadingSessionId] = useState<string | null>(null);
 	const [dirtyDeleteSession, setDirtyDeleteSession] = useState<Session | null>(
 		null,
@@ -62,6 +66,7 @@ export function useInstanceActions(
 		async (session: Session) => {
 			if (loadingSessionId === session.id) return;
 			setLoadingSessionId(session.id);
+			startOperation("start", session.id, session.display_name);
 			try {
 				await startInstance(
 					session.project_id,
@@ -70,18 +75,19 @@ export function useInstanceActions(
 				);
 				await onRefresh();
 			} catch {
-				// ignore
+				completeOperation(session.id, "start", "error");
 			} finally {
 				setLoadingSessionId(null);
 			}
 		},
-		[loadingSessionId, onRefresh],
+		[loadingSessionId, onRefresh, startOperation, completeOperation],
 	);
 
 	const handleStop = useCallback(
 		async (session: Session) => {
 			if (loadingSessionId === session.id) return;
 			setLoadingSessionId(session.id);
+			startOperation("stop", session.id, session.display_name);
 			try {
 				await stopInstance(
 					session.project_id,
@@ -90,18 +96,19 @@ export function useInstanceActions(
 				);
 				await onRefresh();
 			} catch {
-				// ignore
+				completeOperation(session.id, "stop", "error");
 			} finally {
 				setLoadingSessionId(null);
 			}
 		},
-		[loadingSessionId, onRefresh],
+		[loadingSessionId, onRefresh, startOperation, completeOperation],
 	);
 
 	const handleDelete = useCallback(
 		async (session: Session) => {
 			if (loadingSessionId === session.id) return;
 			setLoadingSessionId(session.id);
+			startOperation("delete", session.id, session.display_name);
 			try {
 				await deleteInstance(
 					session.project_id,
@@ -110,8 +117,10 @@ export function useInstanceActions(
 				);
 				setDirtyDeleteSession(null);
 				setDirtyDeleteFiles([]);
+				removeSession(session.id);
 				await onRefresh();
 			} catch (error) {
+				completeOperation(session.id, "delete", "error");
 				const axiosError = error as {
 					response?: {
 						status?: number;
@@ -130,13 +139,20 @@ export function useInstanceActions(
 				setLoadingSessionId(null);
 			}
 		},
-		[loadingSessionId, onRefresh],
+		[
+			loadingSessionId,
+			onRefresh,
+			removeSession,
+			startOperation,
+			completeOperation,
+		],
 	);
 
 	const handleForceDelete = useCallback(
 		async (session: Session) => {
 			if (loadingSessionId === session.id) return;
 			setLoadingSessionId(session.id);
+			startOperation("delete", session.id, session.display_name);
 			try {
 				await deleteInstance(
 					session.project_id,
@@ -146,20 +162,28 @@ export function useInstanceActions(
 				);
 				setDirtyDeleteSession(null);
 				setDirtyDeleteFiles([]);
+				removeSession(session.id);
 				await onRefresh();
 			} catch {
-				// ignore
+				completeOperation(session.id, "delete", "error");
 			} finally {
 				setLoadingSessionId(null);
 			}
 		},
-		[loadingSessionId, onRefresh],
+		[
+			loadingSessionId,
+			onRefresh,
+			removeSession,
+			startOperation,
+			completeOperation,
+		],
 	);
 
 	const handleRecreateTunnel = useCallback(
 		async (session: Session) => {
 			if (loadingSessionId === session.id) return;
 			setLoadingSessionId(session.id);
+			startOperation("recreate-tunnel", session.id, session.display_name);
 			try {
 				await recreateInstanceTunnel(
 					session.project_id,
@@ -167,16 +191,18 @@ export function useInstanceActions(
 					session.id,
 				);
 				await onRefresh();
+				completeOperation(session.id, "recreate-tunnel", "success");
 			} catch (err) {
 				const message =
 					(err as { response?: { data?: { detail?: string } } })?.response?.data
 						?.detail || "Failed to recreate tunnel";
+				completeOperation(session.id, "recreate-tunnel", "error", message);
 				alert(message);
 			} finally {
 				setLoadingSessionId(null);
 			}
 		},
-		[loadingSessionId, onRefresh],
+		[loadingSessionId, onRefresh, startOperation, completeOperation],
 	);
 
 	const handleRename = useCallback(