[ArunaK-netizen]

Resolve #1269 where existing battery widgets fail to update charging status on charger connect/disconnect.

• Overcome Android 8.0+ implicit broadcast restrictions for power connect/disconnect by registering a dynamic BroadcastReceiver in EssentialsApp for 0ms in-memory updates and adding BatteryWidgetJobService (JobScheduler requiresCharging) for background wakeup.
• Fix Glance stale DataStore preference poisoning where cached false locked existing widgets by dynamically reading the sticky Intent.ACTION_BATTERY_CHANGED and BatteryManager in provideGlance.
• Force Glance RemoteViews recomposition by updating a timestamp key across all GlanceIds in updateWidgets.
• Fix crash on widget placement by safely guarding goAsync execution.
• Update widget on user present (screen unlock) and status bar automation events.

Description

Closes #1269

This PR fixes an issue where existing home-screen battery widgets failed to update their charging state (lightning bolt and charging ring) when plugging in or unplugging the charger.

Technical Details:

1. Dynamic Battery State in Glance (BatteriesWidget.kt): Previously, provideGlance fell back to a cached boolean in DataStore. Once the phone was unplugged, false was saved; because false != null, existing widgets were permanently locked into false, ignoring actual hardware status (while newly placed widgets with null preferences rendered correctly). The widget now directly inspects the sticky Intent.ACTION_BATTERY_CHANGED intent and BatteryManager.isCharging.
2. Android 8.0+ Implicit Broadcast Wall (EssentialsApp.kt & BatteryWidgetJobService.kt): Manifest receivers for implicit broadcasts like ACTION_POWER_CONNECTED are dropped by Android OS when the app is in the background. We resolved this across three tiers:
   • Dynamic BroadcastReceiver in EssentialsApp for 0ms latency when the app is in memory.
   • BatteryWidgetJobService (JobScheduler with setRequiresCharging(true)) to wake up and refresh the widget when connected even if the app process was terminated.
   • ACTION_USER_PRESENT in BatteriesWidgetReceiver to refresh widgets immediately when unlocking the screen.
3. Glance Recomposition (BatteriesWidgetReceiver.kt): Added a timestamp key (widget_last_update_ts) so Glance detects state changes and recomposes RemoteViews. Also guarded goAsync() calls to prevent IllegalStateException crashes during initial widget placement.

Type of change

• Bug fix
• New feature
• UI / visual update
• Performance improvement
• Refactoring / cleanup
• Translations
• Build / CI tooling

UI changes

Before	After
before.mp4	after.mp4

Checklist

Before submitting, please make sure:

• The base branch is set to develop (not main).
• The app builds cleanly locally with ./gradlew assembleDebug.
• Unit tests pass with ./gradlew testDebugUnitTest.
• You tested the changes on a device or emulator (including Shizuku or Root if applicable).
• New preferences use SettingsRepository for keys and getter/setter methods.
• New user-facing settings are registered in FeatureRegistry.kt for search indexing.
• New UI follows the design system in ui/core/ (RoundedCardContainer, IconToggleItem, etc.).
• Strings are added to res/values/strings.xml and drawables use rounded variants (R.drawable.rounded_*).