Demo app, collections/features CRUD, QR codes, docs

Demo app (web/):
- Collections: select, rename, remove (x button per row), delete
- Features: add point (lon/lat validation), remove, list in selected collection
- QR codes for pk (private) and pb (public) keys
- Restore public key from private key
- 409 Conflict handled for already-registered login
- Title: Momswap Geo Backend Use-Cases Test

Backend:
- PATCH /v1/collections/{id} for rename
- DELETE /v1/collections/{id}
- Clearer lon/lat validation errors (-180..180, -90..90)

Client:
- updateCollection, deleteCollection, derivePublicKey

Docs:
- docs/frontend-development.md (demo app, local dev)
- README links to all docs

Made-with: Cursor

docs/frontend-development.md

@@ -0,0 +1,70 @@
+# Frontend Development
+
+Development guide for the Momswap Geo demo app (`web/`) and TypeScript client (`libs/geo-api-client`).
+
+## Demo app (`web/`)
+
+Vue 3 + Vuetify 3 single-page app, no bundler. Served by the backend at `/web/`.
+
+### Structure
+
+```
+web/
+├── index.html    # Entry page, Vue/Vuetify from CDN
+├── app.js        # Vue app, state, handlers
+├── api.js        # GeoApiClient wrapper for browser
+└── qr.js         # QR code generation (pk/pb keys)
+```
+
+### Running locally
+
+1. Start the API:
+   ```bash
+   go run ./cmd/api
+   # or: docker compose up -d
+   ```
+2. Open `http://localhost:8122/web/`
+
+### Dependencies
+
+- Vue 3 and Vuetify 3 from CDN (no npm install in `web/`)
+- `libs/geo-api-client/dist/index.js` — built ESM client
+- `qr.js` — imports `qrcode` from esm.sh
+
+### Build step for client
+
+The demo app uses the pre-built client. After changing `libs/geo-api-client`:
+
+```bash
+cd libs/geo-api-client
+bun run build
+```
+
+With Docker, the image build runs this automatically.
+
+### Features (use-cases test)
+
+- Connection & Identity: API URL, key generation, pk/pb display, QR codes, restore pb from pk, register, login
+- Collections: create, select, rename, remove
+- Features: add point (lon/lat validation -180..180, -90..90), remove, list
+
+## TypeScript client (`libs/geo-api-client`)
+
+Reusable API client with Ed25519 signing. See [TypeScript Frontend Integration](typescript-frontend-integration.md) for full API and integration flow.
+
+### Build & test
+
+```bash
+cd libs/geo-api-client
+bun install
+bun test
+bun run build
+```
+
+## Related docs
+
+| Document | Description |
+|----------|-------------|
+| [TypeScript Frontend Integration](typescript-frontend-integration.md) | API client usage, integration flow, examples |
+| [Ed25519 Security Use Cases](ed25519-security-use-cases.md) | Auth flows, registration, signatures |
+| [Geo Auth Backend Plan](geo-auth-backend-plan.md) | Architecture and planning |