[Bug]: Cold background browser launch steals macOS focus

[ankitranjan7]

Description

PR #65 fixed explicit bringToFront() calls during background tab selection and binding, but a cold browser launch still makes Chromium the frontmost macOS application.

This affects the first browser-backed command after the daemon/runtime has stopped. Warm reuse of the same persistent site session behaves correctly.

Related: #66, #65

Steps to Reproduce

Using the current source checkout (v0.3.0, commit 9362750):

1. Stop the daemon and confirm Cloak Chromium is no longer running:

   npm run dev -- daemon stop

2. Put Safari in the foreground.

3. Run a browser-backed command in background mode:

   npm run dev -- twitter whoami --window background -f json

4. Observe the frontmost macOS application throughout the command.

Actual Behavior

The command succeeds, but Chromium takes focus and remains frontmost.

A live focus monitor sampled the cold run as:

focus_before=Safari
focus_after=Chromium
8 Safari samples
18 Chromium samples

After reactivating Safari and immediately repeating the same command against the warm persistent site:twitter lease, all 13 samples remained Safari.

npm run dev -- doctor was green before testing.

Expected Behavior

With --window background, a cold start may create a visible headed Chromium window, but it should remain behind the currently active application. The behavior should match warm-session reuse: no focus theft.

Default/explicit foreground mode should retain its existing behavior.

Root Cause Evidence

The PR #65 path correctly skips bringToFront() for background selection and binding. The cold-launch path is separate:

• getPage() calls getProfileRuntime(profileId) without carrying windowMode into runtime creation.
• launchProfileRuntime() launches Cloak with headless: false and humanize: true, but does not consume windowMode or otherwise prevent/undo native application activation.

The remaining failure is therefore at headed profile/runtime launch, not tab selection or binding.

Acceptance Criteria

• A cold browser-backed command with --window background does not make Chromium frontmost on macOS.
• Warm background commands continue preserving the current foreground application.
• Default and --window foreground behavior remains unchanged.
• Add the smallest regression coverage for propagation through the cold runtime-launch path.
• Verify live on macOS with another application foreground during both cold and warm runs.

Environment

• webcmd source: 0.3.0 at 9362750
• Node.js: 23.11.0
• macOS: 26.5.2 (25F84)