Fix WebGL2 getParameter returning undefined for boolean and integer conformance parameters

[Copilot]

Several WebGL2 getParameter() calls return undefined instead of the required Boolean or Number types, breaking conformance tests and type-dependent application logic.

Changes

Added missing parameter enums:

• WebGLBooleanParameterName: kSampleAlphaToCoverage, kSampleCoverage
• WebGL2BooleanParameterName: kRasterizerDiscard (new enum)
• WebGL2IntegerParameterName: kUniformBufferOffsetAlignment

Backend implementation:

• Added WebGL2Context::getParameterV2(WebGL2BooleanParameterName) method
• Added uniformBufferOffsetAlignment property with lazy GL query and caching
• Updated GetParameter switch statements to route new parameters correctly

Fixed parameters:

// Now return correct types instead of undefined
gl.getParameter(gl.RASTERIZER_DISCARD)              // boolean (was undefined)
gl.getParameter(gl.SAMPLE_ALPHA_TO_COVERAGE)        // boolean (was undefined)
gl.getParameter(gl.SAMPLE_COVERAGE)                 // boolean (was undefined)
gl.getParameter(gl.MAX_3D_TEXTURE_SIZE)             // number >= 256 (was undefined)
gl.getParameter(gl.UNIFORM_BUFFER_OFFSET_ALIGNMENT) // number >= 1 (was undefined)

All changes align with WebGL2 spec §6.3.

Original prompt

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This section details on the original issue you should resolve

<issue_title>WebGL2 context.getParameter returns "undefined" instead of expected types/values for boolean and type checks</issue_title>
<issue_description>### Problem
Some calls to context.getParameter() in the WebGL2 context in JSAR are returning the wrong JS type or an invalid value in critical conformance cases. For example:

• getParameter(context.RASTERIZER_DISCARD) should return a boolean (false by default), but is undefined
• getParameter(context.SAMPLE_ALPHA_TO_COVERAGE) and getParameter(context.SAMPLE_COVERAGE) should return booleans
• getParameter(context.MAX_3D_TEXTURE_SIZE), getParameter(context.UNIFORM_BUFFER_OFFSET_ALIGNMENT), and similar should be non-undefined numbers (integer >= minimum)
• Certain parameters are NOT being returned as instances of Number or Boolean as required, but are undefined or wrong type

Notable FAIL cases

• context.getParameter(context.MAX_3D_TEXTURE_SIZE) should be >= 256. Was undefined
• context.getParameter(context.MAX_3D_TEXTURE_SIZE) is not an instance of Number
• context.getParameter(context.UNIFORM_BUFFER_OFFSET_ALIGNMENT) should be >= 1. Was undefined
• context.getParameter(context.UNIFORM_BUFFER_OFFSET_ALIGNMENT) is not an instance of Number
• context.getParameter(context.RASTERIZER_DISCARD) should be false (boolean) Was undefined
• Similar errors on other boolean/numeric parameters

Expected Behavior

All type checks per WebGL2 and WebGL1 spec should pass: the returned value should always be of the correct type (Boolean, Number) and value as defined. Never undefined.

Impact

• Fails conformance and type safety tests
• Might break application logic depending on typeof/value checks

References

• WebGL2 Spec Table 6.3
• WebGL2 getParameter official mapping

Suggested Actions

• Audit getParameter implementation for value and type safety
• Match Chromium mapping for Number and Boolean return values
• Expand regression tests for typeof/instance conformance

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Category: WebGL2 API type & value conformance</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes WebGL2 context.getParameter returns "undefined" instead of expected types/values for boolean and type checks #421

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