QR scanning:
- BarcodeDetector now snapshots to canvas before detect() instead of passing
live video element — more reliable across Chrome versions
- Uses BarcodeDetector.getSupportedFormats() to detect all formats the browser
supports rather than hardcoding ['qr_code'], catching data_matrix etc.
- jsQR fallback unchanged (attemptBoth inversion)
Processing overlay:
- Added #scan-processing overlay div to _LabelScanModal with spinner + message
- Camera/scanning UI blanks immediately when QR is found or Scan Text tapped;
overlay message differs per path ("QR code found..." vs "Reading label with AI...")
- Overlay hides on error (modal stays open); modal close triggers hideProcessing()
Camera permission:
- localStorage flag (scannerCameraGranted) set on every successful getUserMedia
- preWarmCamera() checks flag first, bypassing navigator.permissions.query which
can return 'prompt' for localhost even when Chrome has 'Allow' internally;
proactive getUserMedia on page load succeeds silently when permission is granted
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
spouliot
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