(CODUX-119) Add desktop update and window-control bridge

[numnx]

🧩 Task: Add desktop update and window-control bridge

Automated task PR opened by Code UX for T01.

📋 Summary

Sprint: Sprint 187 · Fix System Bar · Task: T01

Restore the Electron desktop system bar so it is visible in the app, shows the Code UX version, exposes an update action, and reliably supports maximize/restore by double-clicking the bar.

🤖 Model & Provider

Provider	Codex CLI
Model	gpt-5.5

⏱️ Timing

Started	2026-07-08 12:50:18 UTC
Finished	2026-07-08 12:57:57 UTC
Duration	7m 40s

📊 Token Usage

Metric	Value
Input tokens	71,174
Cached input tokens	1,255,808
Output tokens	8,483
Total tokens	1,335,465
Invocations	1
Tool calls	47
Active time	4m 29s

Included usage estimate (subscription/local login): $1.24

✅ QA Review

⏳ QA review runs after this PR is opened. Check the task card in the dashboard for the outcome once it lands.

📝 Full Task Prompt

## Objective
Add the missing desktop bridge contract needed by the renderer system bar: a safe update action that opens the documented releases page and a testable maximize/restore helper used by Electron IPC.

## Scope
- Create `src/electron/window-controls.ts`
- Edit `src/electron/main.ts`
- Edit `src/electron/preload.ts`
- Edit `dashboard/src/electron-api.d.ts`
- Create `tests/backend/electron/window-controls.test.ts`
- Relevant symbols: `ipcMain.handle("codeux:window-toggle-maximize")`, `ipcMain.handle("codeux:window-state")`, `contextBridge.exposeInMainWorld("codeUxDesktop", ...)`, `CodeUxWindowApi`

## Implementation Requirements
1. Add a small testable helper module in `src/electron/window-controls.ts` that toggles a BrowserWindow-like target between maximized and restored states and returns the resulting `isMaximized` boolean.
2. Update `src/electron/main.ts` so the `codeux:window-toggle-maximize` IPC handler delegates to the helper, preserves current minimize/close/state behavior, and still returns `true` after maximizing and `false` after restoring.
3. Add an IPC handler such as `codeux:open-updates` that opens `https://github.com/codeux-ai/codeux/releases/latest` via Electron `shell.openExternal` and returns whether the request was accepted.
4. Expose the update action through `src/electron/preload.ts` on `window.codeUxDesktop.openUpdates()` without exposing arbitrary URL opening or Node/Electron access.
5. Update `dashboard/src/electron-api.d.ts` so dashboard code can call the new update action with strict TypeScript types.
6. Cover the maximize/restore helper and update URL helper/constant with focused backend tests that use fake window and shell-like objects rather than launching Electron.

## Constraints
- Do not add `electron-updater` or any new dependency; the current documented update flow is GitHub Releases.
- Do not expose a generic external URL opener to the renderer.
- Preserve existing window state persistence, fullscreen state reporting, zoom IPC, and directory picker behavior.
- Keep Electron renderer Node access disabled and continue using the narrow preload bridge.

## Verification
- Run `pnpm run test:backend -- tests/backend/electron/window-controls.test.ts tests/backend/electron/dashboard-network-policy.test.ts`.
- Run `pnpm run lint`.
- Success means the helper restores/maximizes deterministically, the update action targets the official releases URL, and existing Electron network policy tests still pass.

🌿 Branch Info

Base: feature/CODUX-187-fix-system-bar
Head: task/feature-codux-187-fix-system-bar-t01-codex-mrc2soc1

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🤖 Generated by Code UX