feat: tambah deploy pipeline tool di MCP deploy-stg

Tool baru `deploy` menjalankan full pipeline:
1. Cek pending migrations → batalkan jika ada
2. Version bump package.json ke tag baru
3. Commit + push ke build/stg
4. Trigger publish.yml → polling hingga selesai
5. Trigger re-pull.yml → polling hingga selesai
6. Cek version di STG_URL vs local untuk konfirmasi

Env baru: STG_URL (staging app URL), VERSION_PATH (default /api/system/version)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.mcp.json

@@ -5,9 +5,11 @@
       "command": "bun",
       "args": ["scripts/mcp-deploy.ts"],
       "env": {
-        "GH_TOKEN": "",
-        "STACK_NAME": "",
-        "BASE_URL": ""
+        "GH_TOKEN": "${GH_TOKEN}",
+        "STACK_NAME": "${STACK_NAME}",
+        "BASE_URL": "${BASE_URL}",
+        "STG_URL": "${STG_URL}",
+        "VERSION_PATH": "/api/system/version"
       }
     }
   }