feat(core:presentation): UiText, ObserveAsEvents, DataError -> UiText (REDI-82)

- UiText sealed interface (DynamicString / StringResource) — Compose-free type so the
  UI-agnostic presentation module can hold UiText? in state without depending on Compose.
- Two resolvers: @Composable UiText.asString() (Compose renderer) and
  UiText.asString(context) (Views renderer).
- ObserveAsEvents: lifecycle-aware one-time event collection on Main.immediate.
- DataError.toUiText() covering all displayed cases with else -> unknown; error strings here.

core/presentation/build.gradle.kts

@@ -9,4 +9,8 @@ android {
 
 dependencies {
     implementation(project(":core:domain"))
+
+    implementation(libs.androidx.lifecycle.runtime.compose)
+    implementation(libs.androidx.lifecycle.runtime.ktx)
+    implementation(libs.kotlinx.coroutines.android)
 }