#10016: fix: prevent FD exhaustion from skill watcher scanning artifact trees

## Summary - Expand `DEFAULT_SKILLS_WATCH_IGNORED` to cover Python (`venv`, `.venv`, `__pycache__`, `site-packages`, `.tox`, `.mypy_cache`, `.pytest_cache`, `.ruff_cache`, `__pypackages__`, `*.egg-info`), build (`build`, `target`, `.gradle`, `.next`), and `.disabled` directories — prevents chokidar from opening kqueue/inotify FDs for every file in heavy artifact trees - Filter out `.disabled` skill directories from `loadSkillEntries` so renaming a skill dir to `my-skill.disabled` disables it - Exclude artifact directories when copying skills to sandbox workspaces via `syncSkillsToWorkspace` Fixes #9960 ## Test plan - [x] `npx vitest run src/agents/skills/refresh.test.ts` — 5 tests pass (new ignore pattern coverage) - [x] `npx vitest run src/agents/skills/workspace.test.ts` — 4 tests pass (disabled dir filtering + copy exclusion) - [x] `pnpm check` (tsgo + lint + format) — clean - [x] `pnpm test` — 825/825 non-memory test files pass - [ ] Manual: create a skill with a `venv/` containing many files, start gateway, verify FD count stays stable (`lsof -p <pid> | wc -l`) - [ ] Manual: rename a skill dir to `my-skill.disabled`, verify it no longer appears in skill listing 🤖 Generated with [Claude Code](https://claude.com/claude-code) <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR expands the skill watcher ignore list to cover common heavy artifact trees (Python venv/cache dirs, build outputs, Next.js, Gradle, etc.) to prevent chokidar FD exhaustion when scanning large workspaces. It also adds copy-time exclusions when syncing skills into sandbox workspaces, and introduces a `.disabled` convention intended to disable skills by renaming the directory (plus tests for the new ignore/exclusion patterns and workspace sync behavior). <h3>Confidence Score: 4/5</h3> - Mostly safe to merge once the `.disabled` filtering logic is made consistent with the regex-based ignores/excludes. - Changes are scoped and well-tested for the new ignore/exclude patterns, but the `.disabled` filter currently uses `endsWith(".disabled")`, which can fail for trailing-slash baseDir values and break the intended disable-by-rename behavior. - src/agents/skills/workspace.ts <!-- greptile_other_comments_section --> _{(3/5) Reply to the agent's comments like "Can you suggest a fix for this @greptileai?" or ask follow-up questions!} <!-- /greptile_comment -->