iOS Safari can evict blob data from IndexedDB while keeping the Blob
reference intact (instanceof/size checks pass but actual data read
fails). This caused upload POST to throw 'Load failed' client-side,
never reaching the server, burning retries endlessly.
Changes:
- Add validateBlobReadable() that reads first byte to verify data access
- If blob is unreadable, mark as 'failed' immediately with clear message
- Re-read photo from IndexedDB before upload for fresh blob reference
- Capture detailed error name/type in catch for better diagnostics
- Bump SW cache versions to v14/v10 to force new code delivery
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>