Port Bun JSC JIT and Wasm stress matrix

Port the current byte-identical ~/Code/bun/test/js/bun/jsc-stress/jsc-stress.test.ts through Home’s full native VM. The matrix launches 83 real subprocess fixtures spanning baseline/DFG/FTL JS execution plus BBQ/OMG/JSPI Wasm tiers and applies the upstream BUN_JSC_* directive flags.

Baseline under the generic corpus adapter is one native todo. Direct Home full-VM baseline is already 83 pass / 0 fail, so this issue tracks making that native route automatic, preserving byte identity, adding routing regression coverage, and running the full gate. Part of #66; follows #133 and #134.

Completed and pushed in 2647a1bfd (test: port Bun JSC stress matrix).

The byte-identical current ~/Code/bun/test/js/bun/jsc-stress/jsc-stress.test.ts now automatically selects Home’s full native VM. All 83 upstream fixtures pass: 61 baseline/DFG/FTL JavaScript cases and 22 BBQ/OMG/JSPI Wasm cases, each in a real Home subprocess with the upstream BUN_JSC_* directives and preload.

Verification:

• exact normal command: 83 pass, 0 fail, 0 todo
• full ./pantry/.bin/zig build test -Dfilter=home_test --summary failures: pass
• corpus source is byte-identical to current ~/Code/bun

The separate SIMD-baseline HTTP trap is intentionally not hidden here and will be tracked independently.