chore(folio): nest iosApp under app/ for KotlinConf parity

Match KotlinConf-app's filesystem layout where every entry point (android,
ios, web, shared, ui-components) lives under app/. iosApp is still an Xcode
project, not a Gradle module, so settings.gradle.kts is unchanged.

examples/folio/app/iosApp/project.yml

@@ -0,0 +1,43 @@
+name: iosApp
+options:
+  bundleIdPrefix: app.folio
+  deploymentTarget:
+    iOS: "15.0"
+  xcodeVersion: "16.0"
+
+settings:
+  base:
+    ENABLE_USER_SCRIPT_SANDBOXING: NO
+    SWIFT_VERSION: "5.0"
+    ONLY_ACTIVE_ARCH: YES
+    EXCLUDED_ARCHS[sdk=iphonesimulator*]: x86_64
+
+targets:
+  iosApp:
+    type: application
+    platform: iOS
+    sources:
+      - iosApp
+    dependencies:
+      - framework: ../shared/build/bin/iosSimulatorArm64/debugFramework/Shared.framework
+        embed: false
+      - sdk: libsqlite3.tbd
+    settings:
+      base:
+        PRODUCT_BUNDLE_IDENTIFIER: app.folio
+        PRODUCT_NAME: iosApp
+        INFOPLIST_FILE: iosApp/Info.plist
+        FRAMEWORK_SEARCH_PATHS:
+          - $(SRCROOT)/../shared/build/bin/$(KOTLIN_FRAMEWORK_DIR)/debugFramework
+        OTHER_LDFLAGS:
+          - -ObjC
+        KOTLIN_FRAMEWORK_DIR: iosSimulatorArm64
+    preBuildScripts:
+      - name: Build Kotlin framework
+        script: |
+          cd "$SRCROOT/../.."
+          ANDROID_HOME="${ANDROID_HOME:-$HOME/Library/Android/sdk}" \
+            ./gradlew :app:shared:linkDebugFrameworkIosSimulatorArm64
+        outputFiles:
+          - $(SRCROOT)/../shared/build/bin/iosSimulatorArm64/debugFramework/Shared.framework/Shared
+        basedOnDependencyAnalysis: false