v0.25.0:0 - cluster coordination layer (swap lock + webhook + schedule registry)

GPU-arbiter safety layer for when automation, not just the dashboard, swaps
models:
- swap reservation lock (POST/GET/DELETE /api/swap/lock); 423-enforced in
  post_swap via a single-read gate, TTL-bounded, secret-token auth, human
  force-release override + dashboard banner
- swap webhook (swap_complete/swap_failed) fired outside the swap lock, optional
  HMAC signature, configurable URL+secret
- read-only schedule registry (GET/POST/DELETE /api/schedule) + dashboard panel

New module image/app/coordination.py; docs/COORDINATION.md for consumers; 22
offline tests in test_coordination.py.

image/app/static/style.css

@@ -74,6 +74,42 @@ main {
 }
 .banner em { font-style: normal; background: rgba(245, 158, 11, 0.15); padding: 2px 6px; border-radius: 4px; }
 
+/* GPU swap reservation (coordination layer) — informational, not a warning. */
+.lock-banner {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  border-color: var(--info);
+  color: var(--info);
+}
+.lock-banner .lock-icon { font-size: 16px; }
+.lock-banner strong { color: var(--text); }
+.lock-banner .spacer { flex: 1; }
+
+/* Scheduled-jobs panel — read-only view of what external automation registered. */
+.schedule-panel { margin-top: 8px; }
+.schedule-list {
+  display: grid;
+  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
+  gap: 12px;
+  margin-top: 8px;
+}
+.schedule-item {
+  background: var(--surface);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+  padding: 12px 14px;
+}
+.schedule-item .name { font-weight: 600; margin-bottom: 4px; }
+.schedule-item code {
+  background: var(--surface-2);
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  padding: 1px 5px;
+  font-size: 12px;
+}
+.schedule-item .desc { margin-top: 6px; color: var(--muted); font-size: 13px; }
+
 /* ===== Endpoint panel ===== */
 
 .endpoint-panel {