Fix: Nav3 "Key used multiple times" crash (b/516312097)

[StylianosGakis]

Production crash java.lang.IllegalArgumentException: Key HomeKey was used multiple times, thrown by SaveableStateProvider when NavDisplay composes two live entries that share a contentKey. This is the Nav3 framework bug b/516312097.

AI Summary:

Root cause

Two independent contributors, both fixed here:

1. Unstable custom-scene equality. NavEntry.equals compares its content composable lambda by reference identity. Any custom Scene whose equality flows through NavEntry value-equality therefore looks like a brand-new scene whenever that lambda is recreated during a transition, and its contentKey gets registered twice.
2. An auth-driven re-root flap. AuthTokenServiceImpl.authStatus reported LoggedIn purely on token presence. A stored session with an already-expired refresh token would, on cold start, root the app at Home and then get bounced back to Login once the first request's refresh failed, a rapid Login -> Home -> Login re-root that stressed the duplicate-key path.

Changes

• BottomSheetScene now compares equals/hashCode by contentKey instead of by NavEntry identity.
• NavSuiteScene / NavUpBarScene converted from data class to regular classes with explicit key-based equals/hashCode (their key is scene::class to scene.key, already a stable value). NavSuiteScene uses identical logic to NavUpBarScene.
• AuthTokenServiceImpl takes an injected Clock and emits LoggedOut when the stored refresh token is expired (exact expiry), so an unrecoverable session no longer flashes as logged in. The login flow is unaffected: a fresh login writes a future-dated refresh token.
• navigation3 bumped 1.2.0-alpha03 -> 1.2.0-alpha04, which fixes the framework side (comparing OverlayScenes by scene key).