Move replaceCopy function from Copy enum to Helpers module to improve
separation of concerns. Add splitFrontmatter and mergeTagsIntoFrontmatter
utilities for YAML frontmatter manipulation. Remove unused Beautify prompt
and QuickActionsService. Add timeout support to Semaphore.wait(). Remove
unused Event.QuickActionsSettingsChanged. Update all imports across AI
classes, prompts, services, and tests.
