introduce capabilities to knotserver

appview/state/signer.go

···
 
 	return us.client.Do(req)
 }
+
+func (us *UnsignedClient) Capabilities(ownerDid, repoName string) (*http.Response, error) {
+	const (
+		Method   = "GET"
+		Endpoint = "/capabilities"
+	)
+
+	req, err := us.newRequest(Method, Endpoint, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return us.client.Do(req)
+}

knotserver/handler.go

···
 	}
 
 	r.Get("/", h.Index)
+	r.Get("/capabilities", h.Capabilities)
 	r.Get("/version", h.Version)
 	r.Route("/{did}", func(r chi.Router) {
 		// Repo routes

knotserver/routes.go

···
 	w.Write([]byte("This is a knot server. More info at https://tangled.sh"))
 }
 
+func (h *Handle) Capabilities(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+
+	capabilities := map[string]any{
+		"pull_requests": map[string]any{
+			"patch_submissions": true,
+		},
+	}
+
+	jsonData, err := json.Marshal(capabilities)
+	if err != nil {
+		http.Error(w, "Failed to serialize JSON", http.StatusInternalServerError)
+		return
+	}
+
+	w.Write(jsonData)
+}
+
 func (h *Handle) RepoIndex(w http.ResponseWriter, r *http.Request) {
 	path, _ := securejoin.SecureJoin(h.c.Repo.ScanPath, didPath(r))
 	l := h.l.With("path", path, "handler", "RepoIndex")