fix(web): address fourth-pass bugbot review issues

- DirectTerminal: remove stale muxStatus read from xterm setup effect
  (muxStatus was captured at mount, leaving reload button permanently
  disabled); reload button now checks muxStatus directly on each render
- TerminalManager: kill PTY and delete map entry when last subscriber
  unsubscribes, preventing orphaned node-pty processes when all mux
  clients disconnect

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

packages/web/server/mux-websocket.ts

@@ -367,8 +367,12 @@ class TerminalManager {
     // Return unsubscribe function
     return () => {
       terminal.subscribers.delete(callback);
-      // If no subscribers left and PTY is not attached, remove terminal from map
-      if (terminal.subscribers.size === 0 && !terminal.pty) {
+      // Kill PTY and clean up when the last subscriber leaves
+      if (terminal.subscribers.size === 0) {
+        if (terminal.pty) {
+          terminal.pty.kill();
+          terminal.pty = null;
+        }
         this.terminals.delete(id);
       }
     };

packages/web/src/components/DirectTerminal.tsx

@@ -344,9 +344,6 @@ export function DirectTerminal({
           }
         });
 
-        // Update mux status
-        setStatus(muxStatus === "connected" ? "connected" : "connecting");
-
         // Handle window resize
         const handleResize = () => {
           if (fit) {
@@ -533,7 +530,7 @@ export function DirectTerminal({
         {isOpenCodeSession ? (
           <button
             onClick={handleReload}
-            disabled={reloading || status !== "connected"}
+            disabled={reloading || muxStatus !== "connected"}
             title="Restart OpenCode session (/exit then resume mapped session)"
             aria-label="Restart OpenCode session"
             className="ml-auto flex items-center gap-1 px-2 py-0.5 text-[11px] text-[var(--color-text-tertiary)] transition-colors hover:bg-[var(--color-bg-subtle)] hover:text-[var(--color-text-primary)] disabled:cursor-not-allowed disabled:opacity-70"