## Why
Repository skill discovery must reflect current filesystem access, including newly approved grants and narrower permissions. Previously listed skills can remain in conversation history after a turn-scoped grant expires, so catalog updates need to tell the model when availability changes.
## What changed
- Discover repository skills through the selected executor's permission-aware filesystem accessor and refresh snapshots when the working directory or access changes. Use the current step's snapshot for skill selection and invocation.
- Preserve repository boundaries even when project markers are hidden by read restrictions, and report unsupported sandbox backends as skill-loading errors.
- Track grant-dependent catalog entries and emit availability notices when skills disappear or return, even when the metadata budget is exhausted.
- Resolve implicit skill paths through their owning filesystem and exclude remote repository skills from local implicit command attribution.
## Testing
Add coverage for turn and session grants, grant expiry and restoration, hidden and newly created repository markers, cached read denials on Windows, unsupported remote sandboxes, and executor-backed implicit skill paths.
GitOrigin-RevId: ac1af483e73e3130524aeeabe218630435054028
Dmitriy Kovalenko
0b21a5b526