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/typescript-frontend-integration.md

@@ -2,6 +2,8 @@
 
 This document explains how frontend developers should integrate with the backend through the reusable TypeScript client at `libs/geo-api-client`.
 
+> **See also:** [Frontend Development](frontend-development.md) — demo app (`web/`), local dev, build steps.
+
 Primary backend URL for integration:
 
 - `https://momswap.produktor.duckdns.org/`
@@ -43,6 +45,7 @@ Key methods:
 
 - `ensureKeysInStorage()`
 - `getStoredKeys()`
+- `derivePublicKey(privateKey)` — restore public key from private key (Ed25519)
 - `importKeys(keys)`
 - `exportKeys()`
 - `setAccessToken(token)`
@@ -54,8 +57,11 @@ Key methods:
 - `registerWithInvitation(...)`
 - `listCollections()`
 - `createCollection(name)`
+- `updateCollection(collectionId, name)`
+- `deleteCollection(collectionId)`
 - `listFeatures(collectionId)`
 - `createPointFeature(collectionId, lon, lat, properties)`
+- `deleteFeature(featureId)`
 
 ## Recommended integration flow