chore: enhance VSCode settings with formatters and extensions

- Add Biome, Ruff, Dart formatters per language
- Enable organize imports on save
- Add recommended extensions for full stack development

Author: gracefullight

.vscode/extensions.json

@@ -1,5 +1,9 @@
 {
   "recommendations": [
+    "biomejs.biome",
+    "charliermarsh.ruff",
+    "Dart-Code.dart-code",
+    "Dart-Code.flutter",
     "google.arb-editor",
     "hverlin.mise-vscode"
   ]

.vscode/settings.json

@@ -1,3 +1,18 @@
 {
-  "editor.formatOnSave": true
+  "editor.formatOnSave": true,
+  "editor.defaultFormatter": "biomejs.biome",
+  "editor.codeActionsOnSave": {
+    "source.organizeImports.biome": "explicit"
+  },
+  "[python]": {
+    "editor.defaultFormatter": "charliermarsh.ruff"
+  },
+  "[dart]": {
+    "editor.defaultFormatter": "Dart-Code.dart-code"
+  },
+  "typescript.preferences.importModuleSpecifier": "non-relative",
+  "typescript.tsdk": "node_modules/typescript/lib",
+  "files.associations": {
+    "*.arb": "json"
+  }
 }