refactor(folio): introduce nested KotlinConf-style modules

Split the monolithic :composeApp into :core, :app:shared,
:app:ui-components, and :app:androidApp. The old module is still
present and remains the source of truth until the next commits remove
it; both compile in parallel to keep iOS/Android builds green during
the cut-over.

Highlights:
- :core - SQLDelight schema + LedgerStore + Repository (now an
  injectable class, not a singleton object). Methods are suspend to
  match generateAsync = true.
- :app:ui-components - design system primitives. IconButton/AppButton
  APIs revised: label = real contentDescription, testTag = stable
  selector. Drops the data-carrier description argument.
- :app:shared - per-screen ViewModels colocated with screens; pure
  composables on (state, onEvent); LocalAppComponent CompositionLocal
  for hand-rolled DI; @Serializable Route. Hosts the iOS framework
  (baseName Shared).
- :app:androidApp - thin Android entry that constructs the
  DriverFactory and hands it to App().
- gradle/libs.versions.toml centralises versions; settings.gradle.kts
  enables type-safe project accessors.

Deferred to follow-up PRs (per the design discussion):
- Metro DI: hand-rolled AppComponent for now; Metro graphs are mostly
  ceremony for an app this size and add KSP/version risk.
- Navigation3: kept the existing Navigator-as-backstack class,
  injected rather than singleton; nav3 isn't shipping a stable
  multiplatform artifact for commonMain consumption yet.
- :app:webApp + OPFS sqlite worker: web persistence is real new
  wiring (custom worker on @sqlite.org/sqlite-wasm). Master's
  WebLedgerStore + Snapshot is being removed by this PR; web stays
  buildable as a klib but no app-level wasm binary lands here.

examples/folio/app/androidApp/build.gradle.kts

@@ -0,0 +1,44 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.plugin.compose)
+    alias(libs.plugins.compose.multiplatform)
+}
+
+val sanderlingVersion = findProperty("sanderling.version") as String? ?: "0.0.0-dev"
+
+kotlin {
+    compilerOptions { jvmTarget.set(JvmTarget.JVM_17) }
+}
+
+android {
+    namespace = "app.folio"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "app.folio"
+        minSdk = 24
+        targetSdk = 36
+        versionCode = 1
+        versionName = sanderlingVersion
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    buildTypes { debug { isDebuggable = true } }
+
+    sourceSets["main"].apply {
+        manifest.srcFile("src/main/AndroidManifest.xml")
+        res.srcDirs("src/main/res")
+    }
+}
+
+dependencies {
+    implementation(projects.app.shared)
+    implementation(libs.androidx.activity.compose)
+}

examples/folio/app/androidApp/src/main/AndroidManifest.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
+        android:label="Folio"
+        android:allowBackup="false"
+        android:theme="@android:style/Theme.Material.Light.NoActionBar">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:configChanges="orientation|screenSize|screenLayout|keyboardHidden|uiMode|fontScale">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

examples/folio/app/androidApp/src/main/kotlin/app/folio/MainActivity.kt

@@ -0,0 +1,14 @@
+package app.folio
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import app.folio.core.data.DriverFactory
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val driverFactory = DriverFactory(applicationContext)
+        setContent { App(driverFactory) }
+    }
+}