- Add mention parsing and validation logic
- Handle mention entities with proper whitespace
- Validate mention IDs to prevent false positives from code snippets
- Use fake placeholders in tests for privacy
* refactor: consolidate duplicate utility functions
- Add escapeRegExp to src/utils.ts and remove 10 local duplicates
- Rename bash-tools clampNumber to clampWithDefault (different signature)
- Centralize formatError calls to use formatErrorMessage from infra/errors.ts
- Re-export formatErrorMessage from cli/cli-utils.ts to preserve API
* refactor: consolidate remaining escapeRegExp duplicates
* refactor: consolidate sleep, stripAnsi, and clamp duplicates
