Add JoinPage feature with invite token handling and update routing

go_cloud/internal/http/routes.go

@@ -110,6 +110,11 @@ func NewRouter(cfg *config.Config, db *database.DB, jwtManager *jwt.Manager, aut
 	// Health check
 	r.Get("/health", healthHandler)
 
+	// Join org by invite token (public)
+	r.Get("/join", func(w http.ResponseWriter, req *http.Request) {
+		getOrgByInviteTokenHandler(w, req, db)
+	})
+
 	// WOPI routes (public, token validation done per endpoint)
 	r.Route("/wopi", func(r chi.Router) {
 		r.Route("/files/{fileId}", func(r chi.Router) {
@@ -317,6 +322,29 @@ func NewRouter(cfg *config.Config, db *database.DB, jwtManager *jwt.Manager, aut
 	return r
 }
 
+func getOrgByInviteTokenHandler(w http.ResponseWriter, r *http.Request, db *database.DB) {
+	token := r.URL.Query().Get("token")
+	if token == "" {
+		errors.WriteError(w, errors.CodeInvalidArgument, "Token required", http.StatusBadRequest)
+		return
+	}
+
+	var org database.Organization
+	err := db.QueryRowContext(r.Context(), `
+		SELECT id, owner_id, name, slug, created_at
+		FROM organizations
+		WHERE invite_link_token = $1
+	`, token).Scan(&org.ID, &org.OwnerID, &org.Name, &org.Slug, &org.CreatedAt)
+	if err != nil {
+		errors.LogError(r, err, "Invalid invite token")
+		errors.WriteError(w, errors.CodeNotFound, "Invalid token", http.StatusNotFound)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(org)
+}
+
 func healthHandler(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 	w.Write([]byte("OK"))