Implement Note operations

Add notes.go with NoteService for task comment CRUD:
- client.Notes(checklistID, taskID) returns NoteService
- List(ctx) - get all notes on a task (GET /comments.json)
- Create(ctx, comment) - add new note (POST /comments.json)
- Update(ctx, noteID, comment) - update note text (PUT /comments/{id}.json)
- Delete(ctx, noteID) - remove note (DELETE /comments/{id}.json)

All methods support context for cancellation and timeouts.

Closes checkvist-api-5ab

.beads/issues.jsonl

@@ -5,7 +5,7 @@
 {"id":"checkvist-api-1zf","title":"Write unit tests for Filter","description":"Create filter_test.go with tests:\n- TestFilter_WithTag\n- TestFilter_WithMultipleTags\n- TestFilter_WithStatus\n- TestFilter_WithDueBefore\n- TestFilter_WithDueAfter\n- TestFilter_WithDueOn\n- TestFilter_WithOverdue\n- TestFilter_WithSearch\n- TestFilter_Combined\n- TestFilter_Performance_1000Tasks\nUse table-driven tests.","status":"open","priority":1,"issue_type":"task","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:31:38.136650557+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:31:38.136650557+01:00","dependencies":[{"issue_id":"checkvist-api-1zf","depends_on_id":"checkvist-api-1ze","type":"blocks","created_at":"2026-01-14T12:33:14.4378645+01:00","created_by":"Oliver Jakoubek"}]}
 {"id":"checkvist-api-347","title":"Write unit tests for Checklists","description":"Create checklists_test.go with tests:\n- TestChecklists_List\n- TestChecklists_ListArchived\n- TestChecklists_Get\n- TestChecklists_Get_NotFound\n- TestChecklists_Create\n- TestChecklists_Update\n- TestChecklists_Delete\nUse table-driven tests. Create testdata/checklists/ fixtures.","status":"open","priority":0,"issue_type":"task","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:31:37.243525209+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:31:37.243525209+01:00","dependencies":[{"issue_id":"checkvist-api-347","depends_on_id":"checkvist-api-c2k","type":"blocks","created_at":"2026-01-14T12:33:13.512887479+01:00","created_by":"Oliver Jakoubek"}]}
 {"id":"checkvist-api-47y","title":"Quality \u0026 Documentation","description":"Phase 4: Complete unit tests, GoDoc examples, README, and CHANGELOG. Target \u003e80% test coverage. All public functions documented with examples.","status":"open","priority":0,"issue_type":"epic","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:31:36.655509387+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:31:36.655509387+01:00"}
-{"id":"checkvist-api-5ab","title":"Implement Note operations","description":"Create notes.go with NoteService:\n- client.Notes(checklistID, taskID) returns NoteService\n- List(ctx) ([]Note, error) - GET /checklists/{id}/tasks/{task_id}/comments.json\n- Create(ctx, comment string) (*Note, error) - POST /checklists/{id}/tasks/{task_id}/comments.json\n- Update(ctx, noteID, comment string) (*Note, error) - PUT /checklists/{id}/tasks/{task_id}/comments/{note_id}.json\n- Delete(ctx, noteID) error - DELETE /checklists/{id}/tasks/{task_id}/comments/{note_id}.json\nContext support for all methods.","status":"open","priority":0,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:30:54.268124634+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:30:54.268124634+01:00","dependencies":[{"issue_id":"checkvist-api-5ab","depends_on_id":"checkvist-api-rl9","type":"blocks","created_at":"2026-01-14T12:32:55.843507717+01:00","created_by":"Oliver Jakoubek"}]}
+{"id":"checkvist-api-5ab","title":"Implement Note operations","description":"Create notes.go with NoteService:\n- client.Notes(checklistID, taskID) returns NoteService\n- List(ctx) ([]Note, error) - GET /checklists/{id}/tasks/{task_id}/comments.json\n- Create(ctx, comment string) (*Note, error) - POST /checklists/{id}/tasks/{task_id}/comments.json\n- Update(ctx, noteID, comment string) (*Note, error) - PUT /checklists/{id}/tasks/{task_id}/comments/{note_id}.json\n- Delete(ctx, noteID) error - DELETE /checklists/{id}/tasks/{task_id}/comments/{note_id}.json\nContext support for all methods.","status":"closed","priority":0,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:30:54.268124634+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T13:40:31.06124818+01:00","closed_at":"2026-01-14T13:40:31.06124818+01:00","close_reason":"Closed","dependencies":[{"issue_id":"checkvist-api-5ab","depends_on_id":"checkvist-api-rl9","type":"blocks","created_at":"2026-01-14T12:32:55.843507717+01:00","created_by":"Oliver Jakoubek"}]}
 {"id":"checkvist-api-5wr","title":"Initialize Go module and project structure","description":"Create go.mod with module path code.beautifulmachines.dev/jakoubek/checkvist-api. Set up flat package structure with placeholder files: client.go, checklists.go, tasks.go, notes.go, filter.go, models.go, errors.go, options.go. Create magefiles/ directory with separate go.mod for Mage build targets. Add LICENSE (MIT) file.","status":"closed","priority":0,"issue_type":"task","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:31:06.285510329+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:43:45.392753825+01:00","closed_at":"2026-01-14T12:43:45.392753825+01:00","close_reason":"Closed"}
 {"id":"checkvist-api-8bn","title":"Write unit tests for Client and Auth","description":"Create client_test.go with tests using httptest.Server:\n- TestNewClient_Defaults\n- TestNewClient_WithOptions\n- TestAuthenticate_Success\n- TestAuthenticate_InvalidCredentials\n- TestAuthenticate_2FA\n- TestTokenRefresh_Auto\n- TestTokenRefresh_Manual\n- TestCurrentUser\n- TestRetryLogic_429\n- TestRetryLogic_5xx\n- TestRetryLogic_NetworkError\nUse table-driven tests. Create testdata/auth/ fixtures.","status":"closed","priority":0,"issue_type":"task","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:31:36.964610587+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T13:35:19.981723023+01:00","closed_at":"2026-01-14T13:35:19.981723023+01:00","close_reason":"Closed","dependencies":[{"issue_id":"checkvist-api-8bn","depends_on_id":"checkvist-api-lpn","type":"blocks","created_at":"2026-01-14T12:33:12.783142853+01:00","created_by":"Oliver Jakoubek"},{"issue_id":"checkvist-api-8bn","depends_on_id":"checkvist-api-8u6","type":"blocks","created_at":"2026-01-14T12:33:13.232028837+01:00","created_by":"Oliver Jakoubek"}]}
 {"id":"checkvist-api-8jh","title":"Implement repeating tasks configuration","description":"Add P2 (nice-to-have) repeat support to TaskBuilder:\n- WithRepeat(pattern string) *TaskBuilder\nSupport Checkvist smart syntax for repeats.\nDocument common patterns in GoDoc.","status":"open","priority":2,"issue_type":"feature","owner":"mail@oliverjakoubek.de","created_at":"2026-01-14T12:30:56.826106108+01:00","created_by":"Oliver Jakoubek","updated_at":"2026-01-14T12:30:56.826106108+01:00","dependencies":[{"issue_id":"checkvist-api-8jh","depends_on_id":"checkvist-api-tjk","type":"blocks","created_at":"2026-01-14T12:33:03.159849575+01:00","created_by":"Oliver Jakoubek"}]}

notes.go

@@ -1,3 +1,75 @@
 package checkvist
 
+import (
+	"context"
+	"fmt"
+)
+
 // notes.go contains the NoteService for CRUD operations on notes (comments) attached to tasks.
+
+// NoteService provides operations on notes (comments) attached to a specific task.
+type NoteService struct {
+	client      *Client
+	checklistID int
+	taskID      int
+}
+
+// Notes returns a NoteService for performing note operations on the specified task.
+func (c *Client) Notes(checklistID, taskID int) *NoteService {
+	return &NoteService{
+		client:      c,
+		checklistID: checklistID,
+		taskID:      taskID,
+	}
+}
+
+// List returns all notes (comments) attached to the task.
+func (s *NoteService) List(ctx context.Context) ([]Note, error) {
+	path := fmt.Sprintf("/checklists/%d/tasks/%d/comments.json", s.checklistID, s.taskID)
+
+	var notes []Note
+	if err := s.client.doGet(ctx, path, &notes); err != nil {
+		return nil, err
+	}
+	return notes, nil
+}
+
+// createNoteRequest is the request body for creating a note.
+type createNoteRequest struct {
+	Comment string `json:"comment"`
+}
+
+// Create creates a new note (comment) on the task.
+func (s *NoteService) Create(ctx context.Context, comment string) (*Note, error) {
+	path := fmt.Sprintf("/checklists/%d/tasks/%d/comments.json", s.checklistID, s.taskID)
+	body := createNoteRequest{Comment: comment}
+
+	var note Note
+	if err := s.client.doPost(ctx, path, body, &note); err != nil {
+		return nil, err
+	}
+	return &note, nil
+}
+
+// updateNoteRequest is the request body for updating a note.
+type updateNoteRequest struct {
+	Comment string `json:"comment"`
+}
+
+// Update updates an existing note's comment text.
+func (s *NoteService) Update(ctx context.Context, noteID int, comment string) (*Note, error) {
+	path := fmt.Sprintf("/checklists/%d/tasks/%d/comments/%d.json", s.checklistID, s.taskID, noteID)
+	body := updateNoteRequest{Comment: comment}
+
+	var note Note
+	if err := s.client.doPut(ctx, path, body, &note); err != nil {
+		return nil, err
+	}
+	return &note, nil
+}
+
+// Delete permanently deletes a note.
+func (s *NoteService) Delete(ctx context.Context, noteID int) error {
+	path := fmt.Sprintf("/checklists/%d/tasks/%d/comments/%d.json", s.checklistID, s.taskID, noteID)
+	return s.client.doDelete(ctx, path)
+}