feat(terminal): focus management — terminal on open, composer on close

- Opening terminal: xterm.focus() called after fit in the visibility effect
- Closing terminal: ProseMirror editor focused via querySelector after rAF
- Works for all paths: pill click, ⌘+J toggle, trash icon kill

desktop/src/features/terminal/TerminalContext.tsx

@@ -35,6 +35,21 @@ export function TerminalProvider({ children }: { children: React.ReactNode }) {
     };
   }, []);
 
+  // Focus management: return focus to composer when terminal closes.
+  const prevOpenRef = React.useRef(isOpen);
+  React.useEffect(() => {
+    if (prevOpenRef.current && !isOpen) {
+      // Terminal just closed — focus the composer.
+      requestAnimationFrame(() => {
+        const editor = document.querySelector<HTMLElement>(
+          '[data-testid="message-composer"] .ProseMirror',
+        );
+        editor?.focus();
+      });
+    }
+    prevOpenRef.current = isOpen;
+  }, [isOpen]);
+
   const value = React.useMemo(
     () => ({ isOpen, toggle, close }),
     [isOpen, toggle, close],

desktop/src/features/terminal/TerminalInstance.tsx

@@ -212,11 +212,12 @@ export function TerminalInstance({
     };
   }, [channelId, isVisible]);
 
-  // Re-fit when visibility changes.
+  // Re-fit and focus when visibility changes.
   React.useEffect(() => {
     if (isVisible && fitAddonRef.current) {
       requestAnimationFrame(() => {
         fitAddonRef.current?.fit();
+        termRef.current?.focus();
         if (sessionIdRef.current && termRef.current) {
           invoke("terminal_resize", {
             input: {