feat: add PostgreSQL tuner (pgtuner) MCP sidecar

- Add pgtuner MCP sidecar configuration (disabled by default)
- Supports PostgreSQL performance tuning and optimization
- Analyzes slow queries, recommends indexes, detects bloat
- Requires DATABASE_URI secret to be configured
- Runs in SSE mode on port 8085

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

chart/values.yaml

@@ -121,3 +121,16 @@ mcpSidecars:
       limits:
         memory: "256Mi"
         cpu: "500m"
+  pgtuner:
+    enabled: false  # Disabled by default, requires DATABASE_URI in secrets
+    image:
+      repository: dog830228/pgtuner_mcp
+      tag: latest  # TODO: pin to specific version once stable release available
+    port: 8085
+    resources:
+      requests:
+        memory: "64Mi"
+        cpu: "50m"
+      limits:
+        memory: "256Mi"
+        cpu: "500m"