rtodoist 0.4.0

Breaking changes

Added comprehensive test coverage for workspaces, activity logs, backups, templates, and uploads modules
Added skip_if_test_project_missing() helper for more robust integration tests

Updated GitHub Actions workflow to use modern action versions (v2/v4)
Removed debug message from call_api() function
API base URLs now defined as package constants (TODOIST_SYNC_URL, TODOIST_REST_URL)
Fixed glue() to character conversion in templates.R for httr2 compatibility
Improved test robustness by skipping tests when required resources are unavailable
Standardized error handling with req_error() across all REST endpoints
Empty data.frames now return consistent column structure with non-empty results

Fixed templates export/import functions failing due to glue object type issue
Fixed get_comments() empty result missing task_id and project_id columns
Fixed get_all_reminders() empty result missing due_date and minute_offset columns
Fixed get_activity_logs() empty result missing initiator_id, parent_project_id, parent_item_id columns
Fixed get_tasks_by_filter() empty result missing due_date column
Fixed get_archived_projects() empty result missing color and is_favorite columns
Fixed get_all_sections() empty result missing order column
Fixed get_all_workspaces() empty result missing is_default column
Fixed get_workspace_users() empty result missing role column
Fixed quick_add_task() using hardcoded URL instead of TODOIST_REST_URL
Added missing req_error() to quick_add_task() and upload_file()