Polaroid frame component with editable captions and adjustable frame size

[ankitsejwal]

What

Implements the Polaroid component (#3) — each uploaded photo now renders as a classic polaroid.

• White frame with a thicker bottom band (classic look) + drop shadow
• Two editable caption lines per photo, stored per-photo (captionTop / captionBottom); auto-fill from EXIF comes in EXIF auto-caption — date + city via exifr (headline feature) #4
• Adjustable frame size via a slider (settings store), applied live to every polaroid
• Graceful "preview unavailable" fallback inside the frame (e.g. HEIC in Chrome)
• The grid now shows polaroids; remove-on-hover retained

Built as 7 granular commits (model → store action → settings store → font token → component → slider → grid wiring).

Verification

Check	Result
pnpm lint	✅ oxlint 0/0
pnpm typecheck	✅ tsc 7.0.1-rc
pnpm build	✅ Vite 8

Visual: runs live on the dev server. A browser screenshot wasn't captured this round (the shared browser session was locked) — happy to attach one from a fresh isolated session if you want it on the PR.

Notes

• Captions use a handwriting font token with a system-cursive fallback stack (Caveat → Segoe Print → Bradley Hand → cursive) — no external/Google font fetch, keeping the app fully offline/private.

Closes #3