Add bun integration tests for docs flow, update integration guide

- Add test/integration.test.ts: getServicePublicKey, full flow (register, login, createCollection, createPointFeature, listFeatures)
- Update docs example: registerBySigningServiceKey then loginWithSignature
- Document integration tests in typescript-frontend-integration.md

Made-with: Cursor

internal/store/interface.go

@@ -0,0 +1,24 @@
+package store
+
+import "time"
+
+type Store interface {
+	UpsertUser(user User)
+	GetUser(publicKey string) (User, error)
+	CreateChallenge(ch Challenge) error
+	GetChallenge(nonce string) (Challenge, error)
+	MarkChallengeUsed(nonce string) error
+	SaveSession(session Session)
+	GetSession(token string) (Session, error)
+	SaveInvitation(inv Invitation) error
+	GetInvitation(jti string) (Invitation, error)
+	IncrementInvitationUsage(jti string) error
+	SaveCollection(c Collection)
+	ListCollectionsByOwner(owner string) []Collection
+	GetCollection(id string) (Collection, error)
+	SaveFeature(f Feature)
+	ListFeaturesByCollection(collectionID string) []Feature
+	GetFeature(featureID string) (Feature, error)
+	DeleteFeature(featureID string) error
+	PruneExpired(now time.Time)
+}