fix: resolve critical export, preview, trim and memory bugs

[Vedhant26]

Hey folks! 👋 I've taken a deep dive into the critical bugs reported in #930 and put together this PR which resolves all four of the major issues affecting the editing pipeline.

Here's exactly what I've fixed:

1. Export Size Estimation (Preset ID Mismatch): I've removed the hardcoded \PRESET_DIMENSIONS\ object which was out of sync with the actual IDs. The app now directly uses \getPresetById\ to ensure export sizes are predicted accurately for vertical and portrait formats.
2. Preview Crop Geometry: I swapped the inverted logic for the \ill\ crop mode. When the output is taller (e.g. 9:16), it correctly indicates left/right cropping, giving accurate visual feedback!
3. Trim State Leak (NaNs): I created a dedicated \endInput\ state in the \TrimControl\ component. It now waits until all validations pass before firing \onChange, completely preventing invalid states (like \NaN) from bleeding into the global calculations.
4. Thumbnail Strip Memory Usage (OOM fix): I dynamically capped the thumbnail generation interval based on the total video duration. This prevents the browser from generating hundreds of canvases and freezing on long videos.

I've tested these out locally and everything is super smooth and stable now. Let me know if there's anything else you need changed. Cheers! 🚀

Closes #930

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[github-actions]

👋 Thanks for your PR, @Vedhant26!

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[github-actions]

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[Vedhant26]

Issues resolved ! Ready to merge !