fix: prevent macOS background cold launch from stealing focus

[ankitranjan7]

Problem

On macOS, the first browser-backed command after a daemon stop brings Cloak Chromium to the foreground even with --window background. PR #65 removed Webcmd-triggered bringToFront() calls, but a cold Playwright persistent-context launch still activates the Chromium application itself.

Closes #90.

Fix

• cold-launch Cloak Chromium with macOS open -g -n
• reconnect Playwright through a loopback CDP endpoint
• retain Cloak fingerprinting, humanization, profile, and password-store arguments
• explicitly reactivate Chromium only when a later foreground operation requests it
• leave warm sessions and non-macOS launch paths unchanged

Verification

• npm run typecheck
• npm run build
• npm test — 4,166 passed, 1 skipped
• cold background launch: ChatGPT remained frontmost for 30/30 samples
• warm background command: ChatGPT remained frontmost for 15/15 samples
• explicit foreground tab selection moved focus to Chromium