- Remove dead WebAIM email clients link from email-accessibility agent
- Replace deleted cross-shadow ARIA repo with leobalter/cross-root-aria-delegation
- Add 401/406 to GET fallback and BLOCKED_STATUSES in verify-sources.py
- Use browser-compatible User-Agent to avoid bot detection on MDN

Enhanced validator (scripts/validate-agents.js):
- Official GitHub tool alias table validation
- VS Code qualified tool + MCP namespace validation
- Frontmatter property validation against official schema
- Deprecated property detection (infer -> user-invocable)
- Prompt body size check (30K GitHub.com limit, skipped for target: vscode)
- Duplicate tool detection
- Claude Code tool validation (MCP(...) syntax, GitHub tool)
- --strict, --quiet, --files CLI flags

Pre-commit hook:
- scripts/pre-commit validates staged agent/skill files
- scripts/install-hooks.js cross-platform installer
- CI workflow updated with --strict and extended trigger paths

Agent fixes (38 issues resolved):
- Fixed user-invokable typo in 16 agents (property was silently ignored)
- Removed deprecated infer: true from 16 agents
- Removed duplicate search tool from repo-manager
- Added target: vscode to 5 oversized agents

Other:
- MCP server dependency auto-install in install/update scripts
- MCP setup guide in docs/getting-started.md
- Broken link repairs