@remotion/cli: Fix dark mode config option precedence

[JonnyBurger]

Fixes #7766

Summary

• Treat an absent --dark-mode CLI flag as not provided, allowing Config.setChromiumDarkMode(true) from remotion.config.ts to take effect.
• Preserve explicit CLI override behavior for --no-dark-mode.
• Add regression tests for CLI parsing and renderer option precedence.

Testing

• bun test src/test/config-chromium.test.ts
• bun test src/test/dark-mode-option.test.ts
• bun run build
• bun run formatting
• bunx remotion still src/index.ts dark-mode-test /tmp/dark-mode-config.png --log=error with temporary Config.setChromiumDarkMode(true) in packages/example/remotion.config.ts
• ffmpeg -v error -i /tmp/dark-mode-config.png -vf crop=1:1:0:0,format=rgb24 -f rawvideo - | od -An -tx1 returned 1a 1a 1a, matching the dark-mode CSS background.

  

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Project	Deployment	Actions	Updated (UTC)
bugs	Ready	Preview, Comment	May 28, 2026 7:15pm
remotion	Ready	Preview, Comment	May 28, 2026 7:15pm

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