sync-event toasts, image pull ordering, stale banner field diff

- replace chat-bot sync notifications with a dedicated relay_sync_events
  queue: POST/GET /api/sync-events, drained by /api/relay/poll and
  surfaced as stacking toasts via caldav.js. Old /api/chat/bot removed,
  bot=1 rows purged on bootstrap, orange bot rendering dropped from
  relay UI. Chat thread stays clean.
- collab pull: fetch attachments BEFORE applying the body so the moment
  state.cards reflects the new reference the file is on disk. Fixes the
  "preview shows broken/missing image, editor shows it" race where the
  browser cached the 404 between attachment landing and user re-render.
- detail stale banner now compares title/body/color/tags in addition to
  updated_at — robust against second-granularity timestamp collisions
  and any other case where updated_at doesn't tick but content differs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/js/modules/detail.js

@@ -135,7 +135,7 @@ function timeAgo(iso) {
 // After every full card reload, check whether the card we're viewing is
 // newer in the fresh state. If so, show the banner. Dismiss it if the
 // detail view closed in the meantime.
-window.hyprcrd?.hooks?.on?.('cards.reloaded', () => {
+function checkStaleViewingCard() {
     if (!detail.classList.contains('open') || !state.viewingCard) {
         dismissStaleBanner();
         return;
@@ -144,10 +144,19 @@ window.hyprcrd?.hooks?.on?.('cards.reloaded', () => {
     const fresh = state.cards.find(c => c.id == viewingId);
     if (!fresh) return; // card deleted — separate UX, skip banner
     const old = state.viewingCard;
-    if ((fresh.updated_at || '') > (old.updated_at || '')) {
-        showStaleBanner(fresh);
-    }
-});
+    // Compare updated_at OR any field that might have changed. The detail
+    // view captures viewingCard by reference on open, so a replaced
+    // state.cards array (via _reloadAll) gives us a different object — if
+    // any visible field differs, surface the banner.
+    const changed =
+        (fresh.updated_at || '') > (old.updated_at || '') ||
+        (fresh.title || '')      !== (old.title || '')      ||
+        (fresh.body || '')       !== (old.body || '')       ||
+        (fresh.color || '')      !== (old.color || '')      ||
+        (fresh.tags || '')       !== (old.tags || '');
+    if (changed) showStaleBanner(fresh);
+}
+window.hyprcrd?.hooks?.on?.('cards.reloaded', checkStaleViewingCard);
 
 function clearMorphGhost() {
     if (morphTimer) {