Add reaction e2e tests - #60

Summary

• Add Playwright e2e coverage for message reaction flows.
• Add a shared friend-status helper for status constants and friend-status UI actions.
• Add an inject helper for holding and mocking the next /inject request in transaction failure scenarios.
• Update existing friend-status, toll, and video-call specs to reuse the shared friend-status helper.

Tests Added

• user can add, change, and remove a quick reaction
  • Covers adding a quick reaction, sender-side sync for the added reaction, changing the active reaction, sender-side sync for the changed reaction, and local removal by selecting the active reaction again.
• expanded emoji picker sets a custom reaction and surfaces it as active
  • Covers opening the expanded reaction sheet, selecting a custom emoji, rendering the custom reaction chip, marking the custom emoji active in the context menu, and sender-side sync for the custom reaction.
• rolls back an optimistic reaction change when inject fails
  • Covers the optimistic replacement state while /inject is pending, mocked inject failure, rollback to the previous reaction chip, removal of the failed optimistic chip, and context-menu active state after rollback.
• reaction sends are blocked until the message author allows free reactions
  • Covers the toll gate for reactions before the recipient is allowed to react for free, and the blocked-user gate for reaction attempts.