fix: Sync DM read status after modal close and add Android PWA viewport fix

Two critical fixes:

1. DM Badge Sync Issue:
   - After closing DM modal, badge showed correct count for 10 seconds
   - Then auto-refresh (running every 10s) used stale dmLastSeenTimestamps
   - Solution: Call loadDmLastSeenTimestampsFromServer() before updating badge
   - This ensures app.js auto-refresh uses current server state

2. Android PWA Viewport Corruption:
   - Viewport corrupted on F5 refresh in Android PWA mode
   - Status bar content hidden under system UI
   - Solution: Force viewport recalculation on page load
   - Scrolls to top and forces reflow after 100ms delay

Testing needed on Android PWA to verify both fixes work correctly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app/templates/base.html

@@ -262,6 +262,20 @@
     <!-- Custom JS -->
     <script src="{{ url_for('static', filename='js/app.js') }}"></script>
 
+    <!-- PWA Viewport Fix for Android -->
+    <script>
+        // Fix viewport corruption on Android PWA after page reload
+        window.addEventListener('load', function() {
+            // Force viewport recalculation
+            setTimeout(() => {
+                window.scrollTo(0, 0);
+                // Force reflow
+                document.body.style.height = '100%';
+                void(document.body.offsetHeight);
+            }, 100);
+        });
+    </script>
+
     {% block extra_scripts %}{% endblock %}
 </body>
 </html>

app/templates/index.html

@@ -196,6 +196,12 @@
             // Update DM badges when modal is closed (without full page reload)
             dmModal.addEventListener('hidden.bs.modal', async function () {
                 try {
+                    // Reload DM read status from server to sync with app.js automatic updates
+                    // This ensures dmLastSeenTimestamps in app.js is current
+                    if (typeof loadDmLastSeenTimestampsFromServer === 'function') {
+                        await loadDmLastSeenTimestampsFromServer();
+                    }
+
                     // Fetch latest DM conversations with unread counts
                     const response = await fetch('/api/dm/conversations');
                     if (response.ok) {