Add GLSL-based noise(vec2) function to p5.strands (#7897)

[LalitNarayanYadav]

Summary

This PR implements a noise(vec2) function in p5.strands to enable shader-compatible noise effects. It addresses #7897, which is part of the broader effort to bridge core p5.js functions with p5.strands (#7849).

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Changes Made

• Created src/webgl/shaders/functions/noise.glsl.js with a basic fractal noise implementation (3 octaves).
• Registered noise(vec2) in builtInGLSLFunctions in ShaderGenerator.js with isp5Function: false.
• Injected the GLSL noise code into all fragment shaders via GLOBAL_SHADER.output.fragmentDeclarations.add(noiseGLSL).

PR Checklist

• npm run lint passes
• Inline reference is included / updated
• Unit tests are included / updated

[RandomGamingDev]

Looks good to me :D

[davepagurek]

Thanks for tackling this! Are you able to show a test sketch using the noise so we can take a look at what it looks like? Either by making a test sketch in src/preview/global/sketch.js + npm run dev:gloabl, or by running npm run build to generate lib/p5.js and lib/p5.min.js which you could then upload to the p5 web editor and use.

[davepagurek]

I think this might not be defined yet, as we only set GLOBAL_SHADER = this in the ShaderGenerator constructor. Maybe rather than adding noise to the list of glsl functions, we could do a custom function for it like you did earlier for lerp, and in that custom function, you do GLOBAL_SHADER.output.fragmentDeclarations.add(noiseGLSL)? (And possibly add it to the vertex declarations too, it could be used in updating positions as well.)