Add a builtin `a0-setup-cli` skill for guiding host-side A0 connector setup,
and restore the lightweight trigger-word based skill matching flow, which many users asked for.
- add builtin `skills/a0-setup-cli/` with installer-first host setup guidance,
container guardrails, fallback install paths, and example responses
- fix `helpers.skills_cli` so builtin skills under `/skills` are discoverable,
searchable, and validatable
- restore trigger-pattern scoring in runtime `search_skills()`
- re-enable `skills_tool:search` in the current tool flow
- add lightweight lexical relevant-skill recall for the current user message
without reintroducing memory/vector-db skill recall
- update skill prompts to steer the agent toward search/load when requests
match skill trigger phrases
- Extract presets into global presets.yaml; move editor to plugin main screen
- Add project-wide override sync and three-layer permission checks
- Fix embedding change detection, new-chat inheritance, and preset name leak bugs
- Clean up dead imports/params and fix description text
