[narze]

Summary

Chrome Web Store installation and Browse agent control now work in each space.

Chrome Web Store
  download and confirm permissions
  register in the space's extension manager
  restore enabled extensions before pages

Browse extension
  window, tab, action, group, and debugger APIs
  isolated tabs with real documents and usable background viewports

The puzzle menu can run an extension's action on the current tab. Extension-created tabs stay in their space even when link routing targets another profile. Add macOS CI for formatting, types, unit tests, build, and Electron tests.

Evidence

• Before: the store's install button was disabled; Browse's worker crashed on chrome.windows.onRemoved and left setup at “Checking…”. Background automation then stalled on an uninitialized document or a zero-sized viewport.
  After: real store installations, pairing, navigation, a Playwright click, and tab cleanup pass. The rebuilt macOS app also passed the real Browse CLI click test.
• Local validation: pnpm check, 195 unit tests, all 30 app tests with live store/Browse checks enabled, and the packaged-app test passed. The reload lifecycle also passed 10 consecutive regression runs after the worker-registration fix.
• User confirmed the fix; a subsequent request opened Hacker News through the connected m8-browser and read its top story.
• Regression coverage includes the extension-ready and worker-registration/startup boundaries, current-tab actions, profile isolation, and rejection of debugger access to browser controls, other spaces, local files, and browser-wide commands.

Merge Danger

Door: two-way

Existing extension records remain compatible. Reverting removes the added store and runtime support.

Blast Radius: browser

Touches extension loading, page views, and extension API routing. Compatibility is partial: group metadata has no separate group UI; agent tabs use the main window; side panels, recording/offscreen APIs, automatic extension updates, and full multi-window behavior remain unsupported. Live integration tests are opt-in; CI runs the offline suite.