refactor(folio): delete :composeApp and retarget tooling

Removes the old monolithic module now that :core / :app:shared /
:app:ui-components / :app:androidApp own the source. Updates:

- justfile install/uninstall recipes -> :app:androidApp
- iosApp/project.yml framework path -> ../app/shared/...,
  baseName Shared (was ComposeApp); pre-build script invokes
  :app:shared:linkDebugFrameworkIosSimulatorArm64
- iosApp/iosApp/iOSApp.swift -> import Shared
- README -> mentions SQLDelight unification, drops the
  data-carrier contentDescription notes (now stale), no Layout
  section per repo convention

examples/folio/justfile

@@ -40,14 +40,14 @@ install:
     #!/usr/bin/env bash
     set -euo pipefail
     export ANDROID_HOME="$(just _android-home)"
-    ./gradlew :composeApp:installDebug
+    ./gradlew :app:androidApp:installDebug
 
 # Remove the folio APK from the connected device.
 uninstall:
     #!/usr/bin/env bash
     set -euo pipefail
     export ANDROID_HOME="$(just _android-home)"
-    ./gradlew :composeApp:uninstallDebug
+    ./gradlew :app:androidApp:uninstallDebug
 
 # Remove gradle + iOS build directories.
 clean: