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/README.md

@@ -2,14 +2,15 @@
 
 A minimal Kotlin Multiplatform personal-ledger app: login with demo
 credentials, create accounts, add credits and debits. Shared UI across
-Android, iOS, and Web via Compose Multiplatform. Doubles as the example
+Android and iOS via Compose Multiplatform. Doubles as the example
 sanderling runs its property-based specs against.
 
 ## Stack
 
 - Kotlin Multiplatform + Compose Multiplatform (shared UI)
-- kotlinx.serialization for file-backed persistence
+- SQLDelight for the data layer (unified across platforms)
 - kotlinx.coroutines for state flows
+- kotlinx.serialization for `@Serializable` route types
 
 ## Prerequisites
 
@@ -35,8 +36,8 @@ IOS_DEVICE="iPhone 15" just ios   # pick a different simulator
 ```
 
 `just ios` regenerates `iosApp/iosApp.xcodeproj` from `iosApp/project.yml`,
-builds the KMP framework, links it into the SwiftUI host, installs, and
-launches.
+builds the KMP framework (`Shared.framework` from `:app:shared`), links it
+into the SwiftUI host, installs, and launches.
 
 ## Demo credentials
 
@@ -69,9 +70,13 @@ Traces land in `./sanderling/runs/<timestamp>/`.
 
 ## How it connects to sanderling
 
-- UI elements expose state via content descriptions (`account:$id:$balance`,
-  `ledger_row:$id:$signed`, `ledger_balance:$cents`, `active_account:$id`,
-  `focused_input:$field`)
+- Each screen sets a stable Compose `testTag` (`HomeScreen`, `AccountCard`,
+  `LedgerRow`, `TxnAmount`, ...). The Sanderling SDK resolves `testTag` to
+  `resource-id` on Android and `accessibilityIdentifier` on iOS.
+- Identity for list items is the visible text content (account name; txn
+  note + amount). No synthetic IDs encoded in semantics.
+- `contentDescription` is reserved for real accessibility labels, never as a
+  data carrier.
 - `sanderling/spec.ts` imports `@sanderling/spec`, reads state via `s.ax.*`,
-  asserts properties, and weights the actions the fuzzer picks from
-- `just test` invokes `sanderling test` against the installed APK
+  asserts properties, and weights the actions the fuzzer picks from.
+- `just test` invokes `sanderling test` against the installed APK.