Fix WebGPU shader: use bitcast for infinity instead of division by zero
Some WGSL shader validators reject constant division by zero
(output_value_t(-1.0) / output_value_t(0.0)), causing
'Invalid ShaderModule' errors on Windows CI.
Replace with bitcast from IEEE 754 bit patterns:
bitcast<f32>(0xFF800000u) = -inf
bitcast<f32>(0x7F800000u) = +inf
bitcast<f32>() is always valid WGSL (u32→f32 reinterpretation).
output_value_t() then converts f32 inf to f16 inf when the output
type is half-precision (f16 has an infinity representation).
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Justin Chu <justinchu@microsoft.com>