feat(editor): File menu row to connect an external AI agent (Claude/Codex)

Declares the project.connectAgent command id and a File-menu row for it.
The row is optional+pro: only the velxio-prod overlay registers a handler
(it owns accounts, the MCP endpoint and the token flow), so bare OSS hides
the row instead of greying it out — same seam as the account.* commands.

frontend/src/components/editor/EditorMenuBar.tsx

@@ -142,6 +142,15 @@ export const EditorMenuBar: React.FC = () => {
     // pills, one button fewer in the strip.
     { kind: 'command', id: 'project.share', label: t('editor.toolbar.shareLabel', 'Share / Embed') },
     { kind: 'command', id: 'project.githubSync', label: t('editor.toolbar.githubSyncLabel', 'Sync to GitHub'), pro: true },
+    {
+      kind: 'command',
+      id: 'project.connectAgent',
+      label: t('editor.toolbar.connectAgentLabel', 'Connect AI agent (Claude/Codex)'),
+      pro: true,
+      // Only the pro overlay registers a handler; hide (not grey out) the
+      // row in builds where connecting an external agent cannot exist.
+      optional: true,
+    },
     { kind: 'command', id: 'firmware.upload', label: t('editor.toolbar.uploadFirmwareLabel', 'Upload firmware') },
     { kind: 'command', id: 'sim.record', label: t('editor.toolbar.recordLabel', 'Record simulation'), pro: true },
   ];

frontend/src/lib/editorCommands.ts

@@ -37,6 +37,11 @@ export type EditorCommandId =
   | 'help.whatsNew'
   | 'project.share'
   | 'project.githubSync'
+  // Connect an external AI agent (Claude Code / Codex) to the saved
+  // project over MCP. Registered ONLY by the pro overlay (the OSS build
+  // has no accounts, tokens or MCP endpoint), so the menu row hides
+  // itself here — same pattern as the account.* commands.
+  | 'project.connectAgent'
   | 'firmware.upload'
   | 'sim.record'
   | 'sim.compile'