feat: set up Flutter project with drift database, Riverpod providers, and LLM service layer

- Configure dependencies: drift 2.32.x, flutter_riverpod 3.3.1, fl_chart 1.2.x,
  flutter_local_notifications 21.x, local_auth 3.x, and supporting packages
- Drop riverpod_generator (incompatible analyzer version with drift_dev 2.32.x);
  convert all providers to manual Riverpod 3.x API using Notifier<T> and typed families
- Define drift schema: MoodEntries, Activities, EntryActivities, Tags, EntryTags,
  LlmInsights, UserSettings with four DAOs (mood, activity, insight, settings)
- Add LLM service abstraction (LlmService) and MediaPipe implementation
- Fix SettingsDao.delete → deleteByKey to avoid shadowing drift's inherited delete method

.metadata

@@ -0,0 +1,45 @@
+# 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: "cc0734ac716fbb8b90f3f9db8020958b1553afa7"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: android
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: ios
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: linux
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: macos
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: web
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+    - platform: windows
+      create_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+      base_revision: cc0734ac716fbb8b90f3f9db8020958b1553afa7
+
+  # 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'