AIR calls

This subsystem lowers residual stable AIR/LLVM intrinsic calls in the retained SPIR-V module:

• dispatch_texture.rs owns the single call-site dispatcher and texture/query/control intrinsics.
• integer_simd.rs, float_imageblock.rs, reduce_bitops.rs, and matrix_shuffle.rs own numeric, subgroup, imageblock, matrix, and shuffle families.
• agx_emask.rs owns the structurally decoded AGX execution-mask intrinsic family.
• rawbyte_unary.rs, bfloat_glsl.rs, and conversions.rs own raw-resource, unary math, bfloat, and conversion mechanisms.
• images/ owns structural image resolution, coordinate/bounds construction, sampling, gather, query/offset, depth, read, and write helpers used by those call families.

Capability inventory and dispatch share the canonical exact-symbol contract in crate::air_intrinsics. Lowerings still validate operand/result structure. In particular, matrix_shuffle.rs owns both the scalarized 8x8 form and the distributed 32-lane 16x16x16 form; the latter's ABI parser is shared with inventory so recognizing a new element encoding cannot drift away from the implementation that consumes it.