fix: resolve next.js production build compilation errors and worker type mismatches

[thakurakanksha288]

Description

This PR resolves several critical TypeScript compiler errors, ESLint accessibility blocks, and Webpack caching issues that were preventing the production build (npm run build) from completing successfully.

Changes Made

• VideoPreview.tsx: Addressed ESLint jsx-a11y rules for interactive element tracking and matched the framing check to the correct strict "fill" | "fit" types.
• ffmpeg.worker.ts: Implemented a fallback WorkerContext inline interface to bypass missing global DedicatedWorkerGlobalScope types without modifying global configuration scopes.
• constants.ts & frame-export.ts: Unified the recipe data layer by updating legacy rotate property references to the typed rotation field.
• textOverlay.ts: Addressed an optional fallback block by casting the overlay reference dynamically, and mathematically aligned the FFmpeg drawtext coordinates (tw/2, th/2) with the UI's center-origin layout.

Verification

• Wiped the Next.js and Webpack disk caches cleanly.
• Successfully ran npm run build with zero compilation errors.

[vercel]

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[github-actions]

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📖 CONTRIBUTING.md

[github-actions]

👋 Thanks for your PR, @thakurakanksha288!

Welcome to Reframe — a browser-based video editor built for everyone 🎬

What happens next

1. 🤖 Automated checks — build & TypeScript typecheck will run automatically
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Quick checklist

• PR title follows Conventional Commits (e.g. feat: add dark mode)
• Linked the issue this PR closes (e.g. Closes #123)
• Tested the changes locally (bun run dev)
• Build passes (bun run build)

Useful links

• 📖 CONTRIBUTING.md
• 🐛 Open Issues
• ⭐ Star the repo to support the project!

Happy coding! 🎉

[thakurakanksha288]

Hi @magic-peach,

Thank you for reviewing my PR. I noticed that the checks are currently showing "5 workflows awaiting approval" and the build status is still pending, while Vercel deployment requires authorization. Since external contributor workflows require maintainer approval, could you please approve the pending GitHub Actions workflows so the remaining checks can run?

Thank you for your time and support.