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

README.md

@@ -88,6 +88,15 @@ Then visit:
 - Production: `https://momswap.produktor.duckdns.org/web/`
 - Local: `http://localhost:8122/web/`
 
+## Documentation
+
+| Doc | Description |
+|-----|-------------|
+| [docs/frontend-development.md](docs/frontend-development.md) | Demo app (`web/`), client build, local dev |
+| [docs/typescript-frontend-integration.md](docs/typescript-frontend-integration.md) | TypeScript client API, integration flow, examples |
+| [docs/ed25519-security-use-cases.md](docs/ed25519-security-use-cases.md) | Ed25519 auth flows, registration, signatures |
+| [docs/geo-auth-backend-plan.md](docs/geo-auth-backend-plan.md) | Architecture and planning |
+
 ## API client library
 
 Path: `libs/geo-api-client`
@@ -99,11 +108,6 @@ bun test
 bun run build
 ```
 
-Frontend TypeScript integration guide:
-
-- `docs/typescript-frontend-integration.md`
-- `docs/ed25519-security-use-cases.md`
-
 ## CI
 
 Workflow: `.gitea/workflows/ci.yml`