[Feat] (MG_Impl, MG_State, MG_Backend, MG_Util): packed 2_10_10_10 and GL_BGRA vertex array formats

glVertexAttribPointer now accepts the GL 3.3 Core packed types
GL_INT_/GL_UNSIGNED_INT_2_10_10_10_REV and the GL_BGRA size, clearing the
two long-standing "// TODO: implement GL_BGRA support" markers. Adds the
format end to end across the frontend, VAO state, and both backends.

- DataType: add Int2101010Rev / Uint2101010Rev with GLToMG / MGToGL /
  MGToStr converter cases.
- Validation (ValidateVertexAttribFormat): the full glVertexAttribPointer /
  glVertexAttribIPointer error table -- size is 1..4 or GL_BGRA (else
  INVALID_VALUE, which takes precedence); a packed type requires size 4 or
  GL_BGRA (else INVALID_OPERATION); GL_BGRA requires GL_UNSIGNED_BYTE or a
  packed type AND normalized == GL_TRUE (else INVALID_OPERATION); the
  integer path rejects packed types (INVALID_ENUM) and GL_BGRA size
  (INVALID_VALUE).
- VAO: store GL_BGRA as size 4 plus a new IsBgra flag (reset on the
  binding-format path).
- DirectVulkan: map the packed/BGRA formats to
  VK_FORMAT_A2B10G10R10_* (normal) and VK_FORMAT_A2R10G10B10_* /
  VK_FORMAT_B8G8R8A8_UNORM (BGRA reversed), fold IsBgra into the pipeline
  hash, and size packed/BGRA elements as one 4-byte word via
  GetAttributeByteSize. (Vulkan *_SNORM decodes with the GL 4.2 symmetric
  rule, a documented deviation from the 3.3 signed formula.)
- DirectGLES: round-trip the packed enum through the loader, pass GL_BGRA
  as the driver size argument, and size client uploads with the packed
  4-byte word.

Tests: 4 VertexArrayTest cases covering packed/BGRA storage and the full
float/integer error table; the packed-size hard-fail is mutation-verified.
VertexArrayTest 42/42, SanityTest 30/30, library builds clean.

MobileGL/MG_Util/Converters/MGToStr/DataTypeConverter.cpp

@@ -32,6 +32,10 @@ namespace MobileGL {
                 return "Float64";
             case DataType::Fixed32:
                 return "Fixed32";
+            case DataType::Int2101010Rev:
+                return "Int2101010Rev";
+            case DataType::Uint2101010Rev:
+                return "Uint2101010Rev";
             case DataType::Unknown:
             default:
                 return "Unknown";