fix: 终端命令栏被覆盖 — termContainer隔离终端实例

termminal div 用 absolute inset:0 覆盖了底部 cmdBar。
修复: termContainer(flex-1 relative) 容器隔离，cmdBar 作为 flex sibling 在下方。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/app/terminal.html

@@ -36,7 +36,10 @@
   </header>
 
   <!-- Terminal Area -->
-  <div id="terminalArea" class="bg-slate-950 flex flex-col relative">
+  <div id="terminalArea" class="flex-1 min-h-0 flex flex-col relative">
+    <div id="termContainer" class="flex-1 min-h-0 relative">
+      <!-- term instances injected here -->
+    </div>
     <div id="disconnectOverlay" class="hidden absolute inset-0 bg-slate-950/80 backdrop-blur-sm flex flex-col items-center justify-center z-50">
       <div id="disconnectMsg" class="text-slate-300 text-lg mb-1">连接已断开</div>
       <div id="reconnectCountdown" class="text-slate-500 text-sm mb-4 hidden"></div>
@@ -199,7 +202,7 @@ async function newSession(serverId) {
   const div = document.createElement('div');
   div.id = sid;
   div.className = 'term-instance hidden';
-  document.getElementById('terminalArea').prepend(div);
+  document.getElementById('termContainer').prepend(div);
 
   const term = createTerminal();
   const fitAddon = new FitAddon.FitAddon();