- webcam capture resolution/quality configurable in admin settings (defaults 640x480 / 0.92)
- enhance photo modal in journal: original vs preview with sliders (brightness, contrast, saturation, sharpen) and auto-levels button
- new endpoint PUT /api/entries/:id/photo/enhance replaces photo, cleans old file and thumb
- sharper HEIC conversion (0.92) and webp thumbnails (85)
- worker: fail explicitly on empty AI response