Animated bars, inline ProdCom timestamps, fullscreen auto-fit, dual resize corners

Title bars (tiles and the main menubar, which gains the same notch tab)
now collapse and reopen with a height animation instead of popping. The
menubar's hidden state persists per browser. ProdCom timestamps move
inline to the right of the channel name, keeping their text style; the
clock button toggles just their visibility. New fullscreen button (left
of ＋): entering fullscreen auto-hides the menubar and auto-fits the
layout — occupied columns stretch proportionally across the width, tiles
whose bottom edge lands within two rows of the viewport bottom stretch
to end exactly at it, small tiles (h ≤ 2) alone in their columns are
exempt, and scrolling is disabled when nothing extends below the fold
(deeper layouts keep natural rows and scrolling). All fullscreen fitting
is visual-only and reverts on exit; editing affordances are parked while
in it. Corner resize indicators now appear only on tile hover, and a
second resize handle on the bottom-left corner resizes from that edge.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RNYUv9EyrGSFmCnmH7WYKH

public/index.html

@@ -19,6 +19,13 @@
 
     <span class="spacer"></span>
 
+    <button class="tb-btn icon" id="fs-btn" title="Fullscreen — auto-fits the layout to the screen" aria-label="Fullscreen">
+      <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
+        <path d="M4 9V5a1 1 0 0 1 1-1h4"/><path d="M20 9V5a1 1 0 0 0-1-1h-4"/>
+        <path d="M4 15v4a1 1 0 0 0 1 1h4"/><path d="M20 15v4a1 1 0 0 1-1 1h-4"/>
+      </svg>
+    </button>
+
     <div class="dropdown" id="add-dd">
       <button class="tb-btn icon" id="add-btn" title="Add a module tile" aria-label="Add tile">＋</button>
       <div class="menu" id="add-menu" hidden></div>
@@ -43,6 +50,8 @@
     </a>
   </header>
 
+  <button id="topbar-notch" title="Hide / show the menu bar" aria-label="Hide or show the menu bar"></button>
+
   <main id="gridwrap">
     <div id="grid">
       <div id="empty-state">No tiles yet — use “＋ Add tile” to build this dashboard.<br>