fix(android): pause auth polling while backgrounded

[wgqqqqq]

Summary

• pause GitHub device authorization polling while the Android host is backgrounded by OEM browsers or containers
• resume the same authorization transaction immediately when the app returns to the foreground
• retry transient network, timeout, rate-limit, relay, and truncated-response failures without converting them into authentication failures
• add Android lifecycle and authorization diagnostics, and remove the login modal navigation-bar strip

Verification

• :core-feature:jvmTest --tests 'com.openbitfun.mobile.core.feature.account.AccountStoreTest.signInPoll*'
• :app:assembleDebug
• verified login on the connected HarmonyOS phone through 卓易通