feat(igla): Wave Loop 892 — module-scope [603][2]^6 Pt non-power-of-two outer-dimension array-of-struct variable from call with indexed signed writes

[gHashTag]

Next mechanical step in the packed-vector array-of-struct ladder.

• Outer dimension: 603 (non-power-of-two)
• Inner struct: [2]^6 Pt (384 bits per element)
• Total elements: 603 × 64 = 38,592
• Packed vector width: 38,592 × 32 = 1,234,944 bits (~1.178 MiBit)

Pattern: module-scope variable initialized from a pure function call, mutated via signed-index field writes, read back with assert_eq inside a bench block.

Expected zero compiler / FROZEN_HASH changes.

🤖 Generated with Claude Code