Fix critical bugs and clean up debug logging
Bar-raiser review fixes:
- Fix race condition: set g_calendarI2C before Wire.begin()
- Fix Jetstream delete events: look up completion by rkey in cache
- Increase sync limit from 50 to 400 responses (supports full year)
- Add findCompletionByRkey() for reverse rkey lookups
- Add bounds validation for month/day in Jetstream handler
Code cleanup:
- Remove verbose debug logging that caused LED flashing
- Remove dead code: EverydayCalendar_sync.cpp/h (unused serial implementation)
- Remove loop counter debug output from calendar sketch
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>