feat: mobile bottom navigation bar

5-item fixed bottom bar (Dashboard, Focus, Tasks, Calendar, More)
visible only on mobile (<768px). "More" opens a slide-up panel
with links to Notes, Meetings, Decisions, Contacts, Weblinks, Admin.
Active page highlighted with accent color. Desktop unaffected.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

static/app.js

@@ -170,6 +170,13 @@ function escHtml(s) {
 }
 
 
+// ---- Mobile More Panel ----
+
+function toggleMobileMore() {
+    const panel = document.getElementById('mobile-more-panel');
+    if (panel) panel.classList.toggle('open');
+}
+
 // ---- Timer Pill (topbar running timer) ----
 
 let timerStartAt = null;