fix: avoid nested sampler function calls in Color Curves shader

[jtydhr88]

Split nested applyCurve(u_curve0, applyCurve(u_curve1, x)) calls into separate statements using temporary variables. Some WebGL2 GLSL compilers have a bug where nested sampler function parameters cause the outer call to incorrectly use the inner call's sampler, resulting in the curve being applied twice instead of applying two different curves.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between b353a7c and b4156b8.

📒 Files selected for processing (2)

• blueprints/.glsl/Color_Curves_8.frag
• blueprints/Color Curves.json

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📝 Walkthrough

Walkthrough

This pull request refactors the color curve application logic in the Color_Curves_8.frag shader and its corresponding JSON blueprint configuration. The shader now applies per-channel curves (red, green, blue) to intermediate temporary variables first, then applies the RGB master curve to each of these temporary results. Previously, the master curve was applied inline around nested channel curve calls. The evaluation sequence changes from inline computation to an explicit two-step process. No exported or public declarations were modified.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: refactoring nested sampler function calls in the Color Curves shader to avoid a WebGL2 compiler bug.
Description check	✅ Passed	The description clearly explains the fix: splitting nested applyCurve calls into separate statements using temporary variables, and provides context about the WebGL2 compiler bug being addressed.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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