Remove the file mtime check from the API debounce tier in
get_sheet_modified_time(). Previously, the debounce was defeated when
CACHE_TTL_SECONDS differed from CACHE_API_CHECK_TTL_SECONDS because
the file age check would fail even though the API was checked recently.
Also fix cache key mappings (attendance_juniors sheet ID,
payments_transactions rename) and add tmp/ to .gitignore.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Add cache_utils.py with JSON caching for Google Sheets
- Authenticate and cache Drive/Sheets API services globally to reuse tokens
- Use CACHE_SHEET_MAP dict to resolve cache names securely to Sheet IDs
- Change app.py data fetching to skip downloads if modifiedTime matches cache
- Replace global socket timeout with httplib2 to fix Werkzeug timeouts
- Add VS Code attach debugpy configurations to launch.json and Makefile
