Fix Linux CI failure and non-VS-Code Shift+Enter handler scope

- Mock IS_WINDOWS: true in the registry alert test so the Shift+Enter
  handler attaches on Linux CI, where IS_WINDOWS is otherwise false.
- Only route VS Code workbench chords (F1, Ctrl+P, etc.) when the
  platform actually exposes runWorkbenchCommand, so non-VS-Code Windows
  hosts stop silently suppressing the browser default for those keys.

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

Author: dormouse-bot

lib/src/lib/terminal-lifecycle.ts

@@ -117,10 +117,12 @@ function createXtermHost(id: string): { terminal: Terminal; fit: FitAddon; eleme
     },
   });
 
-  // Only hosts that can run workbench commands (the VS Code adapter) opt in;
-  // on every other platform runWorkbenchCommand is undefined, so the chords
-  // stay in xterm exactly as before. Windows Shift+Enter is also normalized
-  // here so terminal apps such as Codex see multiline input instead of Enter.
+  // Two independent reasons to intercept keydown:
+  //   - Windows Shift+Enter needs LF normalization so terminal TUIs see a
+  //     newline instead of Enter (every Windows host, not just VS Code).
+  //   - Hosts that run workbench commands (the VS Code adapter) opt in to
+  //     forwarding F1/Ctrl+P/etc. up to the workbench; non-VS-Code hosts
+  //     leave those chords alone so the browser default still fires.
   if (IS_WINDOWS || getPlatform().runWorkbenchCommand) {
     terminal.attachCustomKeyEventHandler((event) => {
       const shiftEnterInput = shiftEnterInputForEvent(event, {
@@ -133,11 +135,13 @@ function createXtermHost(id: string): { terminal: Terminal; fit: FitAddon; eleme
         handleTerminalInput(id, terminal, shiftEnterInput);
         return false;
       }
+      const runWorkbenchCommand = getPlatform().runWorkbenchCommand;
+      if (!runWorkbenchCommand) return true;
       const command = vscodeWorkbenchCommandForKeydown(event, { isMac: IS_MAC });
       if (!command) return true;
       event.preventDefault();
       event.stopPropagation();
-      getPlatform().runWorkbenchCommand?.(command);
+      runWorkbenchCommand(command);
       return true;
     });
   }

lib/src/lib/terminal-registry.alert.test.ts

@@ -103,8 +103,11 @@ vi.mock('@xterm/xterm', () => {
 vi.mock('./platform', async () => {
   const actual = await vi.importActual<typeof import('./platform')>('./platform');
   const fakePlatform = new actual.FakePtyAdapter();
+  // Force IS_WINDOWS so the Shift+Enter handler is attached regardless of
+  // the host OS this test runs on (Linux CI evaluates it false at module load).
   return {
     ...actual,
+    IS_WINDOWS: true,
     getPlatform: () => fakePlatform,
     __fakePlatform: fakePlatform,
   };