fix(api): rename 'metadata' to 'response_metadata' to avoid Pydantic conflict

The field name 'metadata' conflicts with Pydantic's internal ClassVar.
Renamed to 'response_metadata' throughout:
- Backend: RoutineSuggestion, BatchSuggestion, ShoppingSuggestionResponse
- Frontend: TypeScript types and component usages

This fixes the AttributeError when setting metadata on SQLModel instances.

opencode.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://opencode.ai/config.json",
+  "mcp": {
+    "Playwright": {
+      "type": "local",
+      "command": [
+        "npx",
+        "@playwright/mcp@latest"
+      ]
+    }
+  }
+}