Add comprehensive CHANGELOG following Keep a Changelog format to document
the architecture refactoring and feedback capability implementation.
Documented in v1.0.0:
- ReusableCapabilitiesArchitecture specification
- Feedback capability with visible directory structure
- Detachment facility for capability removal
- Enhanced documentation (CLAUDE.md, README.md, examples)
- Directory visibility changes (.feedback → feedback)
- Explicit family declaration (CAPABILITY-issue-tracking.yaml)
Also includes version history from v0.1.0 through v0.9.0 and
upgrade notes for migrating to v1.0.0.
Closes the documentation gap referenced in TODO.md.
