feat(M13 PBI-31 T-519b/T-520b): NavBar stand-by badge + quota-check runbook (#119)

* feat(M13 T-519b): SSE worker_heartbeat + NavBar stand-by badge

Aanvulling op scrum4me-mcp PR #25 (worker_heartbeat MCP-tool).

- app/api/realtime/solo/route.ts: WorkerHeartbeatPayload type +
  isWorkerHeartbeatPayload guard + shouldEmit-routing op user_id.
- stores/solo-store.ts: workerQuotaPct + workerQuotaCheckAt state +
  setWorkerQuota action. Reset bij decrementWorkers naar 0.
- lib/realtime/use-solo-realtime.ts: handle worker_heartbeat-event,
  roep setWorkerQuota.
- components/solo/nav-status-indicators.tsx: stand-by badge wanneer
  workerQuotaPct < minQuotaPct + tooltip met drempel.
- components/shared/nav-bar.tsx + app/(app)/layout.tsx: minQuotaPct
  prop plumbing van User.min_quota_pct naar NavStatusIndicators.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs(M13 T-520b): pre-flight quota-check sectie in mcp-integration

Documenteert de batch-loop-uitbreiding:
1. get_worker_settings → min_quota_pct
2. bin/worker-quota-probe.sh → pct + reset
3. worker_heartbeat naar server (NavBar stand-by-badge)
4. Sleep tot reset bij low quota; anders wait_for_job

Verwijst naar bin/worker-quota-probe.sh in scrum4me-docker (zie
PR daar).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/shared/nav-bar.tsx

@@ -30,6 +30,7 @@ interface NavBarProps {
   activeProduct: { id: string; name: string } | null
   products: { id: string; name: string }[]
   hasActiveSprint: boolean
+  minQuotaPct: number
 }
 
 export function NavBar({
@@ -41,6 +42,7 @@ export function NavBar({
   activeProduct,
   products,
   hasActiveSprint,
+  minQuotaPct,
 }: NavBarProps) {
   const pathname = usePathname()
   const router = useRouter()
@@ -188,7 +190,7 @@ export function NavBar({
 
       {/* Rechts: solo-status + notifications + account-menu */}
       <div className="flex items-center gap-2 flex-1 justify-end">
-        <SoloNavStatusIndicators hasActiveProduct={!!activeProduct} />
+        <SoloNavStatusIndicators hasActiveProduct={!!activeProduct} minQuotaPct={minQuotaPct} />
         <NotificationsBell currentUserId={userId} isDemo={isDemo} />
         <UserMenu userId={userId} username={username} email={email} roles={roles} />
       </div>

components/solo/nav-status-indicators.tsx

@@ -40,13 +40,28 @@ function RealtimeIndicator({
   )
 }
 
-export function SoloNavStatusIndicators({ hasActiveProduct }: { hasActiveProduct: boolean }) {
+export function SoloNavStatusIndicators({
+  hasActiveProduct,
+  minQuotaPct,
+}: {
+  hasActiveProduct: boolean
+  minQuotaPct: number
+}) {
   const realtimeStatus = useSoloStore((s) => s.realtimeStatus)
   const showConnectingIndicator = useSoloStore((s) => s.showConnectingIndicator)
   const connectedWorkers = useSoloStore((s) => s.connectedWorkers)
+  const workerQuotaPct = useSoloStore((s) => s.workerQuotaPct)
 
   if (!hasActiveProduct) return null
 
+  // M13: stand-by als alle workers low quota hebben (workerQuotaPct geldt
+  // voor de laatste-rapporterende worker; bij N>1 workers is dit een
+  // benadering — server-side aggregate is een v2-verbetering).
+  const isStandby =
+    connectedWorkers > 0 &&
+    workerQuotaPct !== null &&
+    workerQuotaPct < minQuotaPct
+
   return (
     <div className="flex items-center gap-3 px-2">
       <RealtimeIndicator
@@ -56,9 +71,28 @@ export function SoloNavStatusIndicators({ hasActiveProduct }: { hasActiveProduct
       <div className="flex items-center gap-1 text-xs text-muted-foreground">
         <span className={cn(
           'size-2 rounded-full',
-          connectedWorkers > 0 ? 'bg-status-done' : 'bg-muted-foreground/40'
+          isStandby
+            ? 'bg-warning'
+            : connectedWorkers > 0
+              ? 'bg-status-done'
+              : 'bg-muted-foreground/40'
         )} />
-        {connectedWorkers > 0 ? 'Agent verbonden' : 'Geen agent'}
+        {isStandby ? (
+          <TooltipProvider>
+            <Tooltip>
+              <TooltipTrigger
+                render={<span>Stand-by ({workerQuotaPct}%)</span>}
+              />
+              <TooltipContent>
+                Worker wacht tot Anthropic-quota stijgt boven {minQuotaPct}%
+              </TooltipContent>
+            </Tooltip>
+          </TooltipProvider>
+        ) : connectedWorkers > 0 ? (
+          'Agent verbonden'
+        ) : (
+          'Geen agent'
+        )}
       </div>
     </div>
   )