fix: allow devnet url switch from app start intent for qa

[Bilb]

Summary

Lets QA automation point a build at a different devnet seed / service network via launch
intent extras, instead of requiring an app rebuild per target network.

Android apps can't read the launcher's environment, so this is the Android counterpart of
iOS's processUnitTestEnvVariablesIfNeeded: the equivalent channel is intent extras on the
launch activity, which Appium sets with appium:optionalIntentArguments.

'appium:optionalIntentArguments': '--es sessionDevnetSeedUrl http://10.0.0.1:1280'

Supported extras:

Extra	Values
sessionDevnetSeedUrl	http(s) URL; empty clears the override
sessionServiceNetwork	mainnet | testnet | devnet

How it works

• QaLaunchConfig.apply() runs from HomeActivity.onCreate, the launcher target via the
  RoutingActivity alias. It's in the plain onCreate overload rather than
  onCreate(savedInstanceState, ready) because the latter only runs when the base class
  didn't route away — so on a fresh install, exactly the automation case, it never fires.
• Values are persisted to preferences, not held in memory, because the components that read
  them (SnodeDirectory.seedNodePool) are app-scoped singletons that may resolve before or
  after the first activity. They take effect on the next launch; the harness force-restarts
  after the first launch.
• SnodeDirectory records a marker identifying the seed configuration each cached snode pool
  was fetched from, and discards the pool when that configuration changes. Without this, a
  cached pool from the previous network is happily reused and the switch appears to do nothing
  until app data is wiped. The marker is also re-checked before persisting a fetched pool, so a
  config change racing an in-flight fetch can't leave an old-network pool sitting behind an
  already-updated marker.

Security

The launcher alias is android:exported="true", so any app on the device can start it with
extras. Acting on them is gated on BuildConfig.ALLOW_QA_LAUNCH_CONFIG — a compile-time
constant, so R8 strips the reader entirely from builds that don't opt in. It defaults to
false in defaultConfig, is false for release/releaseWithDebugMenu, and true only
for debug/qa/automaticQa. Gating on anything weaker (a runtime pref, a build-type string
compare) would turn an exported launcher into a way for a third-party app to repoint a release
build's network.

Extras parsing is also hardened against a hostile Bundle: a caller can reference a
Parcelable class we don't have, and the unparcel then throws BadParcelableException, which
uncaught is a remote crash-on-launch for every QA build. A malformed Bundle is logged and
treated as no configuration.

Testing

• Verified ALLOW_QA_LAUNCH_CONFIG in the generated BuildConfig for all five build types.
• Malformed / unparseable values are logged and ignored rather than throwing, since this runs
  on the startup path.

[mpretty-cyro]

Not sure if this comment relates to some local changes you have but at the moment I don't think Appium does a force-restart - openAndroidApp in open_app.ts it calls await wrappedDevice.createSession(capabilities)

[mpretty-cyro]

Looks like PathManager persists the onion request paths from previous launches so swapping environments could result in paths from previous launches sticking around (not a huge issue for our use case but might be good to clear it here as well):

private val warmUpJob: Deferred<Unit> = scope.async(start = CoroutineStart.LAZY) {
        val persisted = sanitizePaths(storage.getOnionRequestPaths())
        _paths.update { current -> if (current.isEmpty()) persisted else current }
    }

    init {
        // persist to DB whenever paths change
        scope.launch {
            _paths.drop(1).collectLatest { paths ->
                try {
                    if (paths.isEmpty()) storage.clearOnionRequestPaths()
                    else storage.setOnionRequestPaths(paths)
                } catch (e: Exception) {
                    Log.e("Onion Request", "Failed to persist paths to storage, keeping in-memory only", e)
                }
            }
        }
    }