fix: prevent browser freeze when tessellating >50k vertices (#8219 )

[Nixxx19]

Resolves #8219

Summary

• Adds a one‑time confirmation prompt before tessellating very large TESS shapes (>50,000 vertices) to avoid browser freezes in libtess during _triangulate().
• Cancel: skips tessellation and draws nothing for that shape (no TRIANGLE_FAN fallback), keeping behavior explicit and predictable.
• OK: remembers the choice for the lifetime of the renderer via _largeTessellationAcknowledged and tessellates normally without prompting again.
• Respects p5.disableFriendlyErrors / minified builds: when friendly errors are disabled, tessellation always runs with no prompt.

Tests

• Adds / updates WebGL unit tests in test/unit/webgl/p5.RendererGL.js to cover:
  • Prompting once for large shapes and including the vertex count in the message.
  • Skipping tessellation entirely on cancel (no TRIANGLE_FAN fallback).
  • Only prompting once per renderer when the user approves.
  • Skipping the prompt when p5.disableFriendlyErrors is true.
  • Normal tessellation behavior for shapes below the 50k‑vertex threshold.

Screenshot

PR Checklist

• npm run lint passes
• Inline reference is included / updated (not applicable – bug fix only)
• Unit tests are included / updated

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Thank You!

[davepagurek]

Thanks for working on this! As this is into the main branch, we'll want another PR after this making similar changes into the dev-2.0 branch, where p5 2.x is developed. The code looks like it could largely be the same (but you'll likely want to manually change it on the new base because so much has changed between the branches, merging/rebasing won't be easy), and also how mocking works in tests is a little different as 2.x switched to using vitest.

[davepagurek]

It looks like tests are currently failing here:

   2) Graphics
       p5.Graphics.resizeCanvas
         Rendering
           p5.prototype.resizeCanvas
             p5.Framebuffer
               sizing
                 p5.RendererGL
                   beginShape() in WEBGL mode
                     TESS mode skips prompt when p5.disableFriendlyErrors is true:
     Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.

Does this test also take a while locally?