refactor(sidebar): rebuild footer as priority-driven Ops Pulse strip (#1178)

* refactor(sidebar): rebuild footer as priority-driven Ops Pulse strip

Replace the simple notification ticker with a derived activity summary that
picks one of six states (active-op, failure, automation, recent-event,
quiet-live, disconnected) and routes per-state clicks to logs, schedules,
or activity. The hook owns the cascade; the component is pure presentation;
EditorLayout owns wiring.

Failure detection covers unread errors in the last 24h; recent-event is
limited to non-error stack notifications in the last hour; automation reads
the next /scheduled-tasks?action=update run and a debounced state-invalidate
listener; the deploy-panel composite key is used for elapsed-time tracking
so close-then-immediately-reopen counts as a new session.

* refactor(sidebar): apply Ops Pulse audit fixes

- countEnabledAutoUpdates now defaults missing autoUpdateSettings entries to
  enabled, matching the backend's getStackAutoUpdateSettingsForNode contract.
  Previously the automation state could not render even with the documented
  per-row default-true.
- findFailure now requires a stack_name so the sidebar does not select a
  system-level error whose click would no-op through navigateToNotification.
  System errors continue to surface via the top-bar NotificationPanel.
- DeployPanelState gains a monotonic sessionId sourced from the existing
  internal counter, and the new usePanelSessionStartedAt hook keys the
  elapsed-time tracker off it so a same-stack rerun always resets even when
  isOpen stays true across succeeded then preparing.
- buildConfig splits quiet-live out of the default and adds an exhaustiveness
  guard so future SidebarActivitySummary variants fail to compile.
- New unit tests cover the default-true aggregation, the same-stack session
  reset, the non-stack failure guard, and the useNextAutoUpdateRun debounce
  and cleanup paths. Frontend suite: 276 / 276 pass.

frontend/src/context/DeployFeedbackContext.tsx

@@ -20,6 +20,13 @@ export interface DeployPanelState {
   action: ActionVerb;
   status: 'preparing' | 'streaming' | 'succeeded' | 'failed';
   errorMessage?: string;
+  /**
+   * Monotonic id incremented on every runWithLog call. Lets external
+   * consumers (e.g. the sidebar footer elapsed-time tracker) detect a new
+   * deploy of the same stack+action even when isOpen stays true across the
+   * transition.
+   */
+  sessionId: number;
 }
 
 interface RunResult {
@@ -44,6 +51,7 @@ const DEFAULT_PANEL_STATE: DeployPanelState = {
   stackName: '',
   action: 'deploy',
   status: 'preparing',
+  sessionId: 0,
 };
 
 const DeployFeedbackContext = createContext<DeployFeedbackContextValue | undefined>(undefined);
@@ -109,6 +117,7 @@ export function DeployFeedbackProvider({ children }: { children: React.ReactNode
         stackName: params.stackName,
         action: params.action,
         status: 'preparing',
+        sessionId: mySession,
       });
 
       const deployStarted = new Promise<void>((resolve) => {