[Stretch] Implement reply ranking/voting for template improvement

**Why:** Learn which replies users prefer to improve template engine over time.

**What to build:** Add thumbs-up/down buttons to each reply candidate. Store votes in IndexedDB with reply metadata (text, profile, transcription). Build a simple analytics view showing most-liked templates.

**Acceptance criteria:**
- [ ] Thumbs-up/down buttons on each reply card
- [ ] Votes stored in IndexedDB (object store: reply_votes)
- [ ] Vote metadata: reply text, profile ID, transcription, timestamp, vote (up/down)
- [ ] Analytics view shows top-rated reply patterns
- [ ] Votes do not affect template engine (passive logging only)
- [ ] Privacy: no external data sharing

**Depends on:** #23

Start by reviewing dependency #23 and the existing reply-card entry point, then trace how reply text, profile IDs, and transcriptions are represented. Implement the passive vote flow around the IndexedDB reply_votes object store and add the analytics view. Done means both vote directions persist the specified metadata, top-rated patterns are visible, and template selection is unchanged.

Written by the indexing model from the issue text.