feat(j0.1): squelette projet Flutter + arborescence clean archi

- flutter create --platforms=android --org biz.siteop
- arborescence lib/core/{error,theme,router,di} et lib/features/{locking,playback,podcasts,parental,limits}/{domain,application,data,presentation}
- pubspec.yaml : flutter_riverpod ^2.6.1 (YAGNI — autres paquets aux jalons suivants)
- lib/main.dart : ProviderScope + StorytimeApp (MaterialApp + écran placeholder)
- test/app_boots_test.dart : TDD Red→Green vérifié (flutter test vert, flutter analyze 0 issue)
- README.md : prérequis Flutter 3.41.6 / Dart 3.11.4

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.metadata

@@ -0,0 +1,30 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "db50e20168db8fee486b9abf32fc912de3bc5b6a"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: db50e20168db8fee486b9abf32fc912de3bc5b6a
+      base_revision: db50e20168db8fee486b9abf32fc912de3bc5b6a
+    - platform: android
+      create_revision: db50e20168db8fee486b9abf32fc912de3bc5b6a
+      base_revision: db50e20168db8fee486b9abf32fc912de3bc5b6a
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'