@remotion/renderer: Allow scale factors leading to uneven dimensions

[Copilot]

When rendering videos with H264/H265 codecs, Remotion previously threw errors if scaling resulted in odd dimensions. This was particularly problematic when using scale factors that produced dimensions like 1400x907 (where 907 is odd).

This PR makes the validation more lenient by automatically rounding down odd dimensions to the nearest even number instead of throwing an error.

Changes

• Modified validateEvenDimensionsWithCodec: Instead of throwing errors for odd dimensions, the function now rounds down to the nearest even number
• Added comprehensive test suite: 13 new tests covering various scenarios including the original issue case
• Preserved existing behavior: Other codecs (VP8, VP9, ProRes, etc.) and image sequences are unaffected
• Added logging: Verbose logging when dimension rounding occurs for debugging

Example

Before this change:

// This would throw an error
validateEvenDimensionsWithCodec({
  width: 4000,
  height: 2592, 
  scale: 0.35,  // Results in 1400x907
  codec: 'h264'
});
// Error: height of 907px is an uneven number

After this change:

// This now works and returns { actualWidth: 1400, actualHeight: 906 }
validateEvenDimensionsWithCodec({
  width: 4000,
  height: 2592,
  scale: 0.35,  // Results in 1400x907 → 1400x906
  codec: 'h264'
});

Testing

• ✅ All existing tests pass (257 tests)
• ✅ New comprehensive test suite covers edge cases (13 tests)
• ✅ Original issue case (4000x2592 with scale 0.35) now works correctly
• ✅ Backward compatibility maintained for all other codecs
• ✅ Image sequences continue to allow odd dimensions
• ✅ Linting and formatting checks pass

Fixes #5528.

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Name	Status	Preview	Comments	Updated (UTC)
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