remove: session operations center and progress panel

The bottom-right progress panel duplicated feedback already shown by
toasts. Remove it and the operation-tracking state to simplify the UI:

- Delete state/session-operations.tsx and session-progress-panel.tsx.
- Remove SessionOperationsProvider/SessionProgressPanel from AppShell.
- Remove startOperation/completeOperation calls from useInstanceActions
  and ToolStarter.
- Remove SessionOperationsProvider wrapper from DashboardPage.test.tsx.
- Remove .session-progress-panel CSS rules.
- Format use-events.test.ts mock to match project lint rules.

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

apps/web/src/components/features/tool/tool-starter.tsx

@@ -9,7 +9,6 @@ import {
 } from "../../../api/config-profiles";
 import { listSSHKeys, type SSHKey } from "../../../api/ssh-keys";
 import { useSessions } from "../../../state/sessions";
-import { useSessionOperations } from "../../../state/session-operations";
 import type { Workspace } from "../../../types/workspace";
 import type { ToolInstance } from "../../../api/sessions";
 
@@ -25,7 +24,6 @@ export function ToolStarter({
 	onCancel,
 }: ToolStarterProps) {
 	const { addOrUpdateSession } = useSessions();
-	const { startOperation } = useSessionOperations();
 	const [toolTypes, setToolTypes] = useState<ToolType[]>([]);
 	const [toolTypesLoading, setToolTypesLoading] = useState(true);
 	const [toolTypesError, setToolTypesError] = useState<string | null>(null);
@@ -156,7 +154,6 @@ export function ToolStarter({
 				status: instance.status || "pending",
 				url: instance.url || null,
 			});
-			startOperation("create", instance.id, instance.display_name);
 			onStarted(instance);
 		} catch (err) {
 			setError(err instanceof Error ? err.message : "Failed to start tool");
@@ -171,7 +168,6 @@ export function ToolStarter({
 		onStarted,
 		toolTypes,
 		addOrUpdateSession,
-		startOperation,
 	]);
 
 	return (