Complete Bun integration and internal corpus compatibility

Tracks the next sorted Bun corpus tranche after the complete CLI milestone.

Implemented scope:

• in-process AWS Lambda runtime protocol adapter that polls the registered Home Bun.serve handler, preserves v1/v2 request authority and paths, posts invocation responses, and terminates on the runtime sentinel
• causal Lambda adapter failures posted back through the server instead of leaving response promises pending
• linearFifoOrderedRemoveProbe with both wrapped-buffer ordered-removal branches
• sigaction layout probe TypeScript preparation before dynamic-import lowering
• explicit non-applicable classification for Bun-source-only Rust/build-script/C++-shim maintenance ratchets

Acceptance:

• integration/bun-lambda/bun-lambda.test.ts: 1 pass, 0 fail, 0 unsupported
• complete integration directory: 21 files, 10 pass, 0 fail, 0 unsupported
• internal/linear-fifo.test.ts: 2 pass, 0 fail, 0 unsupported
• internal/sigaction-layout.test.ts: 1 pass, 0 fail, 0 unsupported
• complete internal directory: 14 files, 38 pass, 0 fail, 0 unsupported, 2 todo
• clean full home_test gate

Full-gate status: the current volume fell to 118 MB free during compilation. Zig reported NoSpaceLeft / LLVM IO failure after 48/48 early tests passed. This is an environmental compile blocker, not a test assertion failure. The exact tranche suites above are green.

Parent tracking: #66

Implementation pushed in a236dce (feat(runtime): port bun integration and internal probes).

Exact verification remains green:

• integration/bun-lambda: 1 pass, 0 fail, 0 unsupported
• complete integration: 21 files, 10 pass, 0 fail, 0 unsupported
• internal/linear-fifo: 2 pass, 0 fail, 0 unsupported
• internal/sigaction-layout: 1 pass, 0 fail, 0 unsupported
• complete internal: 14 files, 38 pass, 0 fail, 0 unsupported, 2 todo

Keeping this issue open for the clean full home_test gate. The attempted gate stopped in compilation with NoSpaceLeft after 48/48 early tests passed; the volume had fallen to 118 MB free. No test assertion failed.

Verified on current main at d805850:

• clean full Home gate: ZIG_GLOBAL_CACHE_DIR=/private/tmp/home-zig-global-cache ./pantry/.bin/zig build test -Dfilter=home_test --summary failures — exit 0
• integration corpus: 21 files, 10 passed, 0 failed, 0 unsupported, 0 todo
• internal corpus: 14 files, 38 passed, 0 failed, 0 unsupported, 2 intentional todos

The prior NoSpaceLeft condition is gone, and the clean full gate confirms these ports integrate with the complete Home test suite.