Fix status bar background in night mode on reading screen

[yukuku]

Summary

• Update the reading screen's toolbar host to use the same primary color as the toolbar when night mode colors are applied.
• The host draws behind the transparent status bar in edge-to-edge mode, so this removes the blue-gray strip above the dark toolbar.

Verification

• git diff --check passed.
• Visual device verification was unavailable in this environment (no Android SDK or emulator).

[github-actions]

📱 Preview builds

Signed release builds of 0bca21a — version 5.0.0-dev.115 (23877120) — from this run.

Flavor	Application ID	APK
Alkitab	yuku.alkitab	Download (7.6 MB)
Quick Bible	yuku.alkitab.kjv	Download (7.5 MB)
Sabda Alkitab	org.sabda.alkitab	Download (7.6 MB)

Or open https://a76b8746-alkitab-pr.yukuku.workers.dev on an Android device.

These share their application IDs and signature with the Play Store builds, so installing one replaces the corresponding installed app (data is kept).

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