feat: add comprehensive F32 math library

[victormeloasm]

Adds a comprehensive F32 math library to Bend, modeled after the C math.h API and adapted to Bend's current numeric type system.

The new library includes trigonometric, hyperbolic, exponential, logarithmic, power, rounding, remainder, gamma, error-function, IEEE-754 classification and helper operations, along with common mathematical constants such as PI, E and sqrt(2).

This PR also adds the backend support required for operations that cannot be implemented accurately using only existing F32 primitives, with consistent behavior across the C and JavaScript backends.

Highlights include:

• new bend2/math.bend module
• C99/C11-style math functions applicable to F32
• additional C23-style functions such as sinpi, cospi, tanpi, pown, powr, rootn, rsqrt, exp2m1 and log2p1
• explicit handling for signed zero, subnormals, NaN and infinities
• fused F32 FMA support
• numerically stable implementations for sensitive operations such as expm1, log1p, erf, erfc, scaling and integer powers
• new regression, edge-case and backend consistency tests

Local validation:

• bun gates/repo.ts: PASS 48/48
• randomized C/JS differential testing and IEEE-754 edge-case testing passed
• UBSan, float-cast-overflow, ASan and LeakSanitizer testing passed
• gates/test.ts could not be executed locally because it requires access to the project's private mini-cluster SSH host

[victormeloasm]

Bump