Opens the skill-management-console openspec change (cloud/local skill split
with local override) with proposal, design (D1-D11), four delta specs, and
tasks. Implements the agent-side persistent local skill store
(storage/local_skills.py): authored local skills + cloud-skill overrides in
a physically separate SQLite file, with fork-on-revocation. 10 tests pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
