prefer const variables

Add the const qualifier to variables that are not modified after initialization. This improves code clarity, prevents accidental modifications, and makes the code’s intent more explicit to both compilers and other developers.

Apply const to:

• Local variables that are initialized once and never changed
• Function parameters that are not modified within the function
• Any variable where the value remains constant throughout its scope

Example transformations:

// Before
float2 dsB;
dsB = __half22float2(y_dm[j*MMQ_TILE_Y_K + k01/QI8_1]);

int global_idx = blockIdx.x * blockDim.x + threadIdx.x;
int total_elements = batches * channels * out_h * out_w;

// After  
const float2 dsB = __half22float2(y_dm[j*MMQ_TILE_Y_K + k01/QI8_1]);

const int global_idx = blockIdx.x * blockDim.x + threadIdx.x;
const int total_elements = batches * channels * out_h * out_w;

This practice is especially important in CUDA kernels and performance-critical code where clarity about data mutability helps with optimization and debugging.