[CLAUDE] Skill: Add MCP RAG tools cho 4 sub-agent definitions

Add mcp__rag-unified__search_memory + mcp__rag-unified__cross_project_search
vào tools list 4 agents (Investigator + Implementer + Reviewer + CICD Monitor).

Tại sao:
- Sub-agent spawn KHÔNG inherit MCP server access từ parent session
- 4 agents previously CHỈ có Read/Grep/Glob/Bash → re-read MD files manually
- Plan B pre-flight Investigator phải Read PE Mig 22-26 thủ công thay vì 1 RAG query
- Plan CA Reviewer Cat 1 wire claim verify KHÔNG retrieve historical gotcha cross-session
- Plan CA Hotfix 1 silent sidebar drop nếu Implementer có RAG → catch Pattern 16-bis trước commit

Trade-off accepted (anh chốt full 4 agents):
- Token cost spawn cao hơn (~5-10K extra per RAG query)
- Risk noise dilute focus → mitigate by skill-specific prompt focus

Pitfall #1 reinforced (S27 multi-agent setup):
- Session đang chạy KHÔNG hot-reload registry
- Anh restart Claude Code CLI để spawn S30+ pick up MCP RAG tools
- Plan B Chunk D Implementer đang chạy dùng config CŨ (no MCP) — KHÔNG affect

Verify post-restart (Anh):
- Spawn test Investigator → call mcp__rag-unified__search_memory thử
- Pass = MCP tools loaded; Fail = YAML syntax issue (fallback wildcard mcp__rag-unified__*)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/agents/investigator.md

@@ -2,9 +2,8 @@
 name: investigator
 description: |
   Read-only research and audit specialist for SOLUTION_ERP codebase. Use proactively when main agent needs to scan >5 files for patterns, audit controllers/endpoints, research external sources (Anthropic docs, community blogs), pre-flight reconnaissance before implementation, smoke test endpoints, search V1/V2 workflow schema or sys.triggers, gather reference implementations from similar features (PE → Contract V2 mirror), audit memory entries cross-reference. NEVER writes code — only returns concise structured findings.
-model: claude-opus-4-7
-effort: max
-tools: [Read, Grep, Glob, Bash, WebFetch, WebSearch]
+model: inherit
+tools: [Read, Grep, Glob, Bash, WebFetch, WebSearch, mcp__rag-unified__search_memory, mcp__rag-unified__cross_project_search]
 skills:
   - contract-workflow
   - permission-matrix