Add typed app environment runtime config

[AhmedNMahran]

Summary

This refactors environment selection so mobile-sync can be published once and configured at runtime for either prelive or production.

What changed

• added a typed top-level AppEnvironment API in sync-pipelines
• made AppEnvironment drive both auth and sync defaults together
• kept the lower-level override path for custom endpoints and tests
• refactored auth config to use runtime environment selection instead of relying on BuildKonfig.IS_DEBUG
• updated Android and iOS demo integration to use the new app-level environment API
• added tests for auth environment mapping and app environment sync endpoint mapping
• updated README usage examples and environment guidance

Why

Before this change:

• auth environment was effectively fixed at publish time through buildkonfig.flavor
• sync environment was runtime-configurable through SynchronizationEnvironment
• that mismatch meant one published artifact could not cleanly support both prelive and production auth
• consumers also had to reason about auth and sync environment knobs separately, which made mixed-environment misconfiguration possible

With this change:

• a single published artifact can target either environment at runtime
• AppEnvironment.PRELIVE forces both auth and sync to prelive
• AppEnvironment.PRODUCTION forces both auth and sync to production
• advanced consumers can still use the explicit SynchronizationEnvironment + AuthEnvironment overload if needed

API

Primary API:

val graph = SharedDependencyGraph.init(
    driverFactory = DriverFactory(context = applicationContext),
    appEnvironment = AppEnvironment.PRELIVE
)

Swift:

graph = SharedDependencyGraph.shared.doInit(
    driverFactory: driverFactory,
    appEnvironment: AppEnvironment.prelive
)

Advanced override path remains available:

val graph = SharedDependencyGraph.init(
    driverFactory = DriverFactory(context = applicationContext),
    environment = SynchronizationEnvironment(
        endPointURL = "https://custom-sync.example.com/auth"
    ),
    authEnvironment = AuthEnvironment.PRELIVE
)

Environment behavior
AppEnvironment keeps auth and sync aligned by default:

PRELIVE

• auth: https://prelive-oauth2.quran.foundation
• sync: https://apis-prelive.quran.foundation/auth

PRODUCTION

• auth: https://oauth2.quran.foundation
• sync: https://apis.quran.foundation/auth
• buildkonfig.flavor is now only the fallback default when the app does not pass an explicit app environment.

Validation
Ran successfully:

./gradlew \
  :auth:allTests \
  :sync-pipelines:allTests \
  :sync-pipelines:compileKotlinJvm \
  :sync-pipelines:compileKotlinIosSimulatorArm64 \
  --no-configuration-cache \
  --stacktrace

xcodebuild \
  -project demo/apple/QuranSyncDemo/QuranSyncDemo.xcodeproj \
  -scheme QuranSyncDemo \
  -destination 'generic/platform=iOS Simulator' \
  CODE_SIGNING_ALLOWED=NO \
  build

Impact
This is the right shape for downstream consumers such as quran_android and quran-ios:

• one artifact
• one app-level environment selection
• no need to republish separate prelive/prod auth variants
• lower risk of auth/sync environment drift