chore(01-01): scaffold Flutter project with all dependencies and tooling

- Flutter project created with flutter create (Android platform)
- Runtime deps: flutter_riverpod, riverpod_annotation, drift 2.31, drift_flutter, go_router, path_provider, shared_preferences, flutter_localizations, intl
- Dev deps: riverpod_generator, drift_dev 2.31, build_runner
- Pinned drift/drift_dev to 2.31 for analyzer ^9.0.0 compatibility with riverpod_generator
- Configured l10n.yaml, build.yaml (Drift), analysis_options.yaml (riverpod_lint)
- Minimal ARB file for localization tooling to resolve

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

android/build.gradle.kts

@@ -0,0 +1,24 @@
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+val newBuildDir: Directory =
+    rootProject.layout.buildDirectory
+        .dir("../../build")
+        .get()
+rootProject.layout.buildDirectory.value(newBuildDir)
+
+subprojects {
+    val newSubprojectBuildDir: Directory = newBuildDir.dir(project.name)
+    project.layout.buildDirectory.value(newSubprojectBuildDir)
+}
+subprojects {
+    project.evaluationDependsOn(":app")
+}
+
+tasks.register<Delete>("clean") {
+    delete(rootProject.layout.buildDirectory)
+}