chore(dev): add local-only launch/define workflow and ignore secret define file

.env/flutter_defines.example.json

@@ -0,0 +1,5 @@
+{
+  "SUPABASE_URL": "https://your-project.supabase.co",
+  "SUPABASE_ANON_KEY": "your_anon_key",
+  "SUPABASE_USE_PKCE": "true"
+}

.gitignore

@@ -48,6 +48,10 @@ app.*.map.json
 /supabase_migration.sql
 /TPB_APP_CHECKLIST.md
 
+# Local run configuration with secrets
+/.vscode/launch.json
+/.env/flutter_defines.json
+
 # Local testing artifacts
 /flutter_*.png
 /devtools_options.yaml