feat(api): allow revision comment editing after creation

Add comment field to UpdateRevisionRequest and extend UpdateRevisionStatus
to accept an optional comment parameter. The PATCH /api/items/{partNumber}/revisions/{revision}
endpoint now accepts a comment field alongside status and labels.

Closes #174

internal/api/handlers.go

@@ -1058,10 +1058,11 @@ type RevisionDiffResponse struct {
 	Changed      map[string]db.PropertyChange `json:"changed,omitempty"`
 }
 
-// UpdateRevisionRequest represents a request to update revision status/labels.
+// UpdateRevisionRequest represents a request to update revision status/labels/comment.
 type UpdateRevisionRequest struct {
-	Status *string  `json:"status,omitempty"`
-	Labels []string `json:"labels,omitempty"`
+	Status  *string  `json:"status,omitempty"`
+	Labels  []string `json:"labels,omitempty"`
+	Comment *string  `json:"comment,omitempty"`
 }
 
 // RollbackRequest represents a request to rollback to a previous revision.
@@ -1164,12 +1165,12 @@ func (s *Server) HandleUpdateRevision(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// Validate that at least one field is being updated
-	if req.Status == nil && req.Labels == nil {
-		writeError(w, http.StatusBadRequest, "invalid_request", "Must provide status or labels to update")
+	if req.Status == nil && req.Labels == nil && req.Comment == nil {
+		writeError(w, http.StatusBadRequest, "invalid_request", "Must provide status, labels, or comment to update")
 		return
 	}
 
-	err = s.items.UpdateRevisionStatus(ctx, item.ID, revNum, req.Status, req.Labels)
+	err = s.items.UpdateRevisionStatus(ctx, item.ID, revNum, req.Status, req.Labels, req.Comment)
 	if err != nil {
 		if err.Error() == "revision not found" {
 			writeError(w, http.StatusNotFound, "not_found", "Revision not found")

internal/api/revision_handlers_test.go

@@ -150,6 +150,31 @@ func TestHandleUpdateRevision(t *testing.T) {
 	}
 }
 
+func TestHandleUpdateRevisionComment(t *testing.T) {
+	s := newTestServer(t)
+	router := newRevisionRouter(s)
+
+	createItemDirect(t, s, "REVCMT-001", "update comment", nil)
+
+	body := `{"comment":"updated comment"}`
+	req := authRequest(httptest.NewRequest("PATCH", "/api/items/REVCMT-001/revisions/1", strings.NewReader(body)))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status: got %d, want %d; body: %s", w.Code, http.StatusOK, w.Body.String())
+	}
+
+	var rev RevisionResponse
+	if err := json.Unmarshal(w.Body.Bytes(), &rev); err != nil {
+		t.Fatalf("decoding response: %v", err)
+	}
+	if rev.Comment == nil || *rev.Comment != "updated comment" {
+		t.Errorf("comment: got %v, want %q", rev.Comment, "updated comment")
+	}
+}
+
 func TestHandleCompareRevisions(t *testing.T) {
 	s := newTestServer(t)
 	router := newRevisionRouter(s)

internal/db/items.go

@@ -491,8 +491,8 @@ func (r *ItemRepository) GetRevision(ctx context.Context, itemID string, revisio
 }
 
 // UpdateRevisionStatus updates the status and/or labels of a revision.
-func (r *ItemRepository) UpdateRevisionStatus(ctx context.Context, itemID string, revisionNumber int, status *string, labels []string) error {
-	if status == nil && labels == nil {
+func (r *ItemRepository) UpdateRevisionStatus(ctx context.Context, itemID string, revisionNumber int, status *string, labels []string, comment *string) error {
+	if status == nil && labels == nil && comment == nil {
 		return nil // Nothing to update
 	}
 
@@ -524,6 +524,12 @@ func (r *ItemRepository) UpdateRevisionStatus(ctx context.Context, itemID string
 		argNum++
 	}
 
+	if comment != nil {
+		updates = append(updates, fmt.Sprintf("comment = $%d", argNum))
+		args = append(args, *comment)
+		argNum++
+	}
+
 	query += updates[0]
 	for i := 1; i < len(updates); i++ {
 		query += ", " + updates[i]

internal/db/items_edge_test.go

@@ -105,7 +105,7 @@ func TestRevisionStatusUpdate(t *testing.T) {
 	}
 
 	status := "released"
-	if err := repo.UpdateRevisionStatus(ctx, item.ID, 1, &status, nil); err != nil {
+	if err := repo.UpdateRevisionStatus(ctx, item.ID, 1, &status, nil, nil); err != nil {
 		t.Fatalf("UpdateRevisionStatus: %v", err)
 	}
 
@@ -129,7 +129,7 @@ func TestRevisionLabelsUpdate(t *testing.T) {
 	}
 
 	labels := []string{"prototype", "urgent"}
-	if err := repo.UpdateRevisionStatus(ctx, item.ID, 1, nil, labels); err != nil {
+	if err := repo.UpdateRevisionStatus(ctx, item.ID, 1, nil, labels, nil); err != nil {
 		t.Fatalf("UpdateRevisionStatus: %v", err)
 	}