collab per-card unread, detail stale banner, image sync race fix

- per-card unread dot on board (collab-buckets): backend tracks
  last_seen_at per card, poll exposes unread_cards, frontend decorates
  matching board cards; cleared on any open path via detail.opened hook
- detail.opened + cards.reloaded hooks on the hyprcrd event bus
- stale banner in detail view with manual Reload when the currently
  viewed card got updated by a peer — no content swap under the user
- collab image sync: push attachments BEFORE card (race fix) + pull-side
  self-heal scans every collab card for missing uploads each poll
- relay user deletion now purges chat_messages sent by deleted user so
  ghost threads stop appearing for their peers
- calendar header nav buttons styled as square bordered buttons that
  honor --ui-radius-button; title bar widened to 280px so font variants
  don't wrap
- .toolbar-btn now uses var(--ui-radius-button) instead of hardcoded 3px

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

public/js/modules/detail.js

@@ -72,9 +72,83 @@ export function openDetail(id, options = {}) {
 
     renderSidebar(card);
     showContent(card);
+    dismissStaleBanner();
     detail.classList.add('open');
+
+    // Let plugins (collab-buckets unread-dot, etc.) react to the open.
+    window.hyprcrd?.hooks?.emit?.('detail.opened', { id: card.id });
 }
 
+// ── Remote-update detection ──
+//
+// When a foreign edit arrives for the card the user is currently viewing,
+// the pull replaces state.cards but the open detail view keeps rendering
+// the stale object it captured on open. Instead of force-re-rendering
+// under the user's finger (jarring when they're mid-read), surface a
+// banner with a manual Reload button.
+
+let staleBannerEl = null;
+
+function dismissStaleBanner() {
+    if (staleBannerEl) { staleBannerEl.remove(); staleBannerEl = null; }
+}
+
+function showStaleBanner(fresh) {
+    dismissStaleBanner();
+    const host = detail.querySelector('#detail-controls')?.parentElement;
+    if (!host) return;
+    const bar = document.createElement('div');
+    bar.className = 'detail-stale-banner';
+    bar.innerHTML = `
+        <i class="ph ph-info"></i>
+        <span>This card was updated${fresh?.updated_at ? ' ' + timeAgo(fresh.updated_at) : ''}.</span>
+        <button class="detail-stale-reload">
+            <i class="ph ph-arrows-clockwise text-xs"></i>
+            <span>Reload</span>
+        </button>
+        <button class="detail-stale-dismiss" aria-label="Dismiss"><i class="ph ph-x text-xs"></i></button>
+    `;
+    host.insertBefore(bar, host.querySelector('#detail-controls').nextSibling);
+    staleBannerEl = bar;
+    bar.querySelector('.detail-stale-reload').addEventListener('click', () => {
+        const current = state.cards.find(c => c.id == state.viewingCard?.id);
+        if (current) {
+            state.viewingCard = current;
+            renderSidebar(current);
+            showContent(current);
+        }
+        dismissStaleBanner();
+    });
+    bar.querySelector('.detail-stale-dismiss').addEventListener('click', dismissStaleBanner);
+}
+
+function timeAgo(iso) {
+    const t = new Date(iso).getTime();
+    if (!isFinite(t)) return '';
+    const s = Math.max(0, (Date.now() - t) / 1000);
+    if (s < 60)  return `${Math.floor(s)}s ago`;
+    if (s < 3600) return `${Math.floor(s / 60)}m ago`;
+    if (s < 86400) return `${Math.floor(s / 3600)}h ago`;
+    return `${Math.floor(s / 86400)}d ago`;
+}
+
+// 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', () => {
+    if (!detail.classList.contains('open') || !state.viewingCard) {
+        dismissStaleBanner();
+        return;
+    }
+    const viewingId = state.viewingCard.id;
+    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);
+    }
+});
+
 function clearMorphGhost() {
     if (morphTimer) {
         clearTimeout(morphTimer);
@@ -370,6 +444,7 @@ export function closeDetail(options = {}) {
     closeImageFullscreen();
 
     detail.classList.remove('open', 'zen');
+    dismissStaleBanner();
     removeZenHandles();
     document.documentElement.classList.remove('detail-zen-open');
     document.body.classList.remove('detail-zen-open');