Add ratings and reviews #40

Summary

Add ratings and reviews feature to Android client. Currently not implemented on any platform except Web.

Required Work

1. Data Models

• Rating (user_id, content_id, score 1-10 or thumbs, timestamp)
• Review (user_id, content_id, title, body, rating, timestamp, helpful_count)
• AggregateRating (content_id, average_score, total_ratings, distribution)

2. API Integration

• GET /api/v2/ratings/{content_id} - get aggregate + user's rating
• POST /api/v2/ratings - submit/update rating
• DELETE /api/v2/ratings/{content_id} - remove rating
• GET /api/v2/reviews/{content_id} - list reviews (paginated)
• POST /api/v2/reviews - submit review
• PATCH /api/v2/reviews/{review_id} - update review
• DELETE /api/v2/reviews/{review_id} - delete review
• POST /api/v2/reviews/{review_id}/helpful - mark helpful

3. UI Components

• RatingDisplay - show aggregate stars/score + user's rating
• RatingInput - star picker or thumbs up/down
• ReviewList - paginated list with sorting (recent, helpful, rating)
• ReviewCard - display single review with author, rating, body
• ReviewComposer - write/edit review sheet

4. Integration Points

• TitleDetailScreen - show aggregate rating + user's rating
• Episode list - show episode ratings
• Profile - show user's ratings/reviews

Files to Modify/Create

• androidApp/src/main/kotlin/org/prairieserver/prairie/android/ui/screens/detail/TitleDetailScreen.kt
• androidApp/src/main/kotlin/org/prairieserver/prairie/android/ui/screens/detail/RatingDisplay.kt (NEW)
• androidApp/src/main/kotlin/org/prairieserver/prairie/android/ui/screens/detail/RatingInput.kt (NEW)
• androidApp/src/main/kotlin/org/prairieserver/prairie/android/ui/screens/detail/ReviewList.kt (NEW)
• androidApp/src/main/kotlin/org/prairieserver/prairie/android/ui/screens/detail/ReviewComposer.kt (NEW)
• androidTvApp/src/main/kotlin/org/prairieserver/prairie/tv/ui/screens/detail/ - TV variants
• shared/src/commonMain/kotlin/org/prairieserver/prairie/model/rating/ - NEW: shared models

Reference Implementation

• Web: prairie-server/web/src/components/RatingDisplay.tsx, ReviewList.tsx
• Server: internal/apiv2/ratings.go, internal/apiv2/reviews.go