## Summary
- The Capacitor shell buys through StoreKit (iOS 15) and Play Billing instead of RevenueCat.
- After the store sheet succeeds, the app POSTs the signed transaction or Play purchase token to `/monetization/store/confirm/`.
- Restore reads current store entitlements and confirms each one. Web checkout stays on Stripe.
- The store account token from `GET /monetization/subscription/` is sent as `appAccountToken` / `obfuscatedAccountId`.
Depends on the `chat_backend` PR for issue #78 (`feat/78-native-store-purchases`).
## Test plan
- [x] `storeBilling`, `revenueCat`, `finance`, and `BillingSection` unit tests
- [ ] iOS sandbox purchase and restore against a backend with `APPLE_IAP_BUNDLE_ID` set
- [ ] Play license-test purchase and restore against a backend with `GOOGLE_PLAY_SERVICE_ACCOUNT_JSON` set
- [ ] Web billing still opens Stripe Checkout
Reviewed-on: #122
## Summary
- Closes [#97](#97) — message action row: copy (raw markdown + code-block copy), thumbs up/down with optimistic updates + down-reason popover, and export menu (PDF / DOCX / CSV / XLSX / TXT) for a single message plus conversation-level export in the chat toolbar.
- Closes [#98](#98) — versioned WS `citations` frame parsing, Sources list under assistant bubbles, clickable `[n]` markers, and history hydrate from `Prompt.citations`.
- Backend companion for ratings: [chat_backend#67](ai_ml_operations/chat_backend#67). Thumbs UI posts to `prompt_feedback` once that lands; votes rehydrate from `conversation_details.feedback`.
- Export libs (`pdfmake`, `docx`, `papaparse`, `xlsx`) are dynamically imported so they stay out of the main path until used.
## Test plan
- [ ] Stream a grounded answer → Sources appear after stream; inline `[n]` highlights the matching source; reload keeps Sources.
- [ ] Non-grounded turn → no Sources header.
- [ ] Copy message + code block; confirm checkmark ~2s; failure path shows toast.
- [ ] Thumbs up/down optimistic UI; clear by re-click; down opens reason popover without blocking the vote (needs chat_backend#67).
- [ ] Export one message and whole conversation in all five formats; check searchable PDF text and DOCX structure.
- [ ] Action row: hover reveal on desktop, always visible on last/touch; hidden while streaming.
- [ ] `npm test -- --testPathPattern='wsFrames|clipboard|exportChat|promptFeedback|ConversationDetailCard'`Reviewed-on: #101
westfarn