Add label create, update, and delete operations

[wesnick]

Summary

Implements full CRUD operations for Gmail labels via the gwcli labels command group. Users can now create, update (rename/change visibility), and delete labels in addition to the existing list/apply/remove operations.

Changes

• New command handlers (labels.go):

  • runLabelsCreate() - Create a new user label with optional visibility settings
  • runLabelsUpdate() - Rename a label or change its message/label list visibility
  • runLabelsDelete() - Permanently delete a user label (requires --force flag)

• New connection methods (pkg/gwcli/connection.go):

  • CreateLabel() - Calls gmail.Users.Labels.Create API
  • UpdateLabel() - Calls gmail.Users.Labels.Patch API
  • DeleteLabel() - Calls gmail.Users.Labels.Delete API
  • invalidateLabels() - Clears label cache after mutations so subsequent operations reload from API
  • Initialize messageCache and labelCache in NewFake() for testing

• CLI command definitions (main.go):

  • labels create <name> - Create label with optional --message-list-visibility and --label-list-visibility flags
  • labels update <label-id> - Update label by name or ID with optional --name, --message-list-visibility, --label-list-visibility flags
  • labels delete <label-id> - Delete label by name or ID, requires --force flag

• Comprehensive test suite (labels_test.go):

  • TestRunLabelsCreate - Verify label creation with JSON output
  • TestRunLabelsCreateEmptyName - Reject empty label names
  • TestRunLabelsCreateDuplicate - Reject duplicate names (case-insensitive)
  • TestRunLabelsUpdate - Verify label rename with name resolution
  • TestRunLabelsUpdateNoChanges - Reject updates with no fields provided
  • TestRunLabelsDelete - Verify label deletion with JSON output
  • TestRunLabelsDeleteRequiresForce - Require --force flag
  • TestRunLabelsDeleteSystemLabel - Prevent deletion of system labels (INBOX, SENT, etc.)

• Documentation (CLAUDE.md):

  • Updated label operations section with new commands and implementation details
  • Documented visibility flag mappings and safety features

Implementation Details

• Duplicate detection: create checks existing labels case-insensitively before creating
• System label protection: delete prevents removal of Gmail system labels (type="system") with a clear error message
• Label resolution: Both update and delete accept label name or ID, resolved via the shared resolveLabelID() helper
• Cache invalidation: All mutations call invalidateLabels() to ensure subsequent operations see fresh data from the API
• Visibility flags: Map to Gmail API fields:
  • --message-list-visibility: show or hide
  • --label-list-visibility: labelShow, labelShowIfUnread, or labelHide
• Output formats: All operations support both JSON (--json) and human-readable text output
• Safety: delete requires explicit --force flag (non-interactive rule Refactor app into single root command #3 from CLAUDE.md)

https://claude.ai/code/session_01UdqRpUFcLqZQjFpDDkbnxk