docs: add inline reference for uniform* methods in p5.strands

[Anshumancanrock]

Resolves #8439

Changes:

Added inline reference documentation for the uniform* methods in p5.strands. These methods are used in strands shader callbacks to pass data from JavaScript into shader code, but previously had no reference pages.

Documented methods:

• uniformFloat() - single float value (includes 2 examples: with callback + manual setUniform)
• uniformInt() - integer value
• uniformBool() - boolean toggle
• uniformVec2() - 2D vector
• uniformVec3() - 3D vector
• uniformVec4() - 4D vector (RGBA colors, etc.)
• uniformTexture() - texture sampling via getTexture()

Each entry includes a description, parameter/return info, usage examples, and notes about aliases (e.g. uniformVector2(), uniformSampler2D()).

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