fix(hud): polish performance layout and zero opacity

[papi-ux]

Summary

• split the performance HUD into a dedicated FPS/target/sparkline row and a separate latency/bitrate/resolution/codec row
• scale panel shadow elevation with the selected HUD opacity so the 0% preset leaves no faint glass box
• keep telemetry text and the sparkline signal readable while removing only panel chrome
• add source guards and a physical-device Compose geometry test for row separation

Why

The added performance details were competing horizontally with the FPS display, and the panel shadow remained visible even when the opacity preset was set to 0%.

Verification

• targeted source guards: RED before implementation, GREEN after
• ./gradlew -PnovaAbis=x86_64 testNonRoot_gameDebugUnitTest --tests 'com.papi.nova.ui.NovaComposeSourceGuardTest.performanceHudSeparatesFpsFromDetailMetrics' --tests 'com.papi.nova.ui.NovaComposeSourceGuardTest.zeroOpacityScalesPanelShadowToZero' --tests 'com.papi.nova.ui.NovaComposeSourceGuardTest.streamHudUsesCompactBoundedLabels'
• ./gradlew -PnovaAbis=x86_64 -PlintFailOnError=true lintNonRoot_gameDebug testNonRoot_gameDebugUnitTest
• ./gradlew -PnovaAbis=arm64-v8a assembleNonRoot_gameDebug
• ./gradlew -PnovaAbis=arm64-v8a connectedNonRoot_gameDebugAndroidTest -Pandroid.testInstrumentationRunnerArguments.class=com.papi.nova.ui.NovaHudPerformanceLayoutComposeTest
  • 1/1 passed on physical Retroid Pocket 6 (Android 13)
• bash scripts/check-public-docs.sh
• git diff --check

Safety

• based on clean origin/master in an isolated worktree
• does not modify the existing dirty Nova checkout