Moves the Zap button from the message thread header to the message composer area, adjacent to the Send button. Refactors the Zap interface creation logic into a standalone component `ZapInterface.js` to decouple it from `MessageThread.js`. Updates `Composer.js` to support an optional `onZap` handler and renders the button with an icon-only style matching the video player's accent interaction. Updates `AppShell.js` to orchestrate the Zap interface display.
Removes the "Direct message privacy" section from the profile modal's Messages tab, as these settings are now managed via the AppShell (gear icon).
- Removed privacy section HTML from `components/profile-modal.html`.
- Updated `js/ui/profileModalController.js` to remove legacy DOM references and event listeners.
- Preserved `handleReadReceiptsToggle` and `handleTypingIndicatorsToggle` methods for AppShell integration.
- Updated `syncDmPrivacySettingsUi` to be a no-op to prevent errors in existing call sites.
google-labs-jules[bot]