REFACTOR(app): simplify tool architecture

MAJOR SIMPLIFICATION:
- Removed 20+ specialized MCP tools
- Added 3 universal tools: bash_command, read_file, write_file
- All agents now use the same tools (behavior controlled by prompts)

Changes:
1. Added universal_tools (bash-centric approach):
   - bash_command: Execute any bash command (kubectl, git, npm, python, etc.)
   - read_file: Read files (convenience wrapper)
   - write_file: Write files (convenience wrapper)

2. All agents now use universal_tools:
   - orchestrator (Claude)
   - backend_developer (Groq)
   - frontend_developer (Groq)
   - sre_specialist (Groq)
   - yaml_manager (Groq)

3. Updated orchestrator prompt:
   - Focus on bash_command usage
   - Clear examples of bash commands
   - Simpler, more powerful approach

4. Legacy tools kept for backward compatibility:
   - Old specialized tools still available but not recommended
   - Use bash_command instead

Benefits:
- Extreme simplicity: 3 tools vs 20+
- Complete autonomy: Agents can do anything via bash
- Maintainable: No need to add new tools, just use bash

deploy/k8s/overlays/prod/kustomization.yaml

@@ -16,5 +16,5 @@ commonLabels:
 # 이미지 태그 설정 (ArgoCD Image Updater가 자동으로 업데이트)
 images:
   - name: gitea0213.kro.kr/bluemayne/mas
-    newTag: main-sha-5d100114b3be48ae14d58b4b7faf46be908f1e42
+    newTag: main-sha-d44ac52b35e0911abbf467c1439f15edff47f61b