feat(ui): add Portable Chrome Nova theme

[papi-ux]

Summary

• Adds a Portable Chrome theme to Nova matching the Polaris dim Moonlight-grey early-2000s silver palette
• Wires the theme into settings, theme cycling, app/settings styles, Android 12 splash colors, and Compose library surfaces
• Keeps status/silver readability restrained with dark text and muted blue/green accents

Test Plan

• RED: ./gradlew testDebugUnitTest --tests com.papi.nova.ui.NovaThemeManagerTest --tests com.papi.nova.ui.NovaThemeResourcesTest --tests com.papi.nova.ui.compose.NovaLibrarySurfacesTest failed before implementation with missing THEME_PORTABLE_CHROME/resources
• ./gradlew testDebugUnitTest --tests com.papi.nova.ui.NovaThemeManagerTest --tests com.papi.nova.ui.NovaThemeResourcesTest --tests com.papi.nova.ui.compose.NovaLibrarySurfacesTest
• git submodule update --init --recursive app/src/main/jni/moonlight-core/moonlight-common-c
• ./gradlew testDebugUnitTest assembleRootDebug lintRootDebug