fix(ui): deepen PSP chrome theme

[papi-ux]

Summary

• Deepens the PSP / Portable Chrome palette into smoked graphite so it reads less washed-out on handheld screens
• Darkens the silver surface family by about 19 luma points on average while preserving dark readable text
• Strengthens PSP shell seams/scrims and calms particles/focus glow for a sleeker retro handheld feel

Test Plan

• RED: PSP shade tests failed against the previous washed silver palette
• ./gradlew testDebugUnitTest --tests com.papi.nova.ui.NovaThemeManagerTest --tests com.papi.nova.ui.compose.NovaLibrarySurfacesTest
• ./gradlew testDebugUnitTest assembleRootDebug lintRootDebug
• aapt dump --values resources app/build/outputs/apk/root/debug/app-root-arm64-v8a-debug.apk verified darker PSP resource values and PSP / Portable Chrome label
• adb install -r -d -g app/build/outputs/apk/root/debug/app-root-arm64-v8a-debug.apk on Retroid Pocket 6
• run-as prefs verify nova_theme=portable_chrome
• monkey launch confirmed com.papi.nova.root.debug/com.papi.nova.ui.NovaLibraryActivity resumed
• adb screencap luma sample: mean 175.7, p95 200.3, >220 pixels 0.13%