feat(bookstack-api-7qx): implement Comments CRUD

Add CommentsService with List, Get, Create, Update, Delete.
Support nested comments via parent_id. Register service on Client.
Add types and tests.

comments.go

@@ -0,0 +1,56 @@
+package bookstack
+
+import (
+	"context"
+	"fmt"
+)
+
+// CommentsService handles operations on comments.
+type CommentsService struct {
+	client *Client
+}
+
+// List returns a list of comments with optional filtering.
+func (s *CommentsService) List(ctx context.Context, opts *ListOptions) ([]Comment, error) {
+	var resp listResponse[Comment]
+	err := s.client.do(ctx, "GET", "/api/comments"+opts.queryString(), nil, &resp)
+	if err != nil {
+		return nil, err
+	}
+	return resp.Data, nil
+}
+
+// Get retrieves a single comment by ID.
+func (s *CommentsService) Get(ctx context.Context, id int) (*Comment, error) {
+	var c Comment
+	err := s.client.do(ctx, "GET", fmt.Sprintf("/api/comments/%d", id), nil, &c)
+	if err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+// Create creates a new comment on a page.
+func (s *CommentsService) Create(ctx context.Context, req *CommentCreateRequest) (*Comment, error) {
+	var c Comment
+	err := s.client.do(ctx, "POST", "/api/comments", req, &c)
+	if err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+// Update updates an existing comment.
+func (s *CommentsService) Update(ctx context.Context, id int, req *CommentUpdateRequest) (*Comment, error) {
+	var c Comment
+	err := s.client.do(ctx, "PUT", fmt.Sprintf("/api/comments/%d", id), req, &c)
+	if err != nil {
+		return nil, err
+	}
+	return &c, nil
+}
+
+// Delete deletes a comment by ID.
+func (s *CommentsService) Delete(ctx context.Context, id int) error {
+	return s.client.do(ctx, "DELETE", fmt.Sprintf("/api/comments/%d", id), nil, nil)
+}