fix: backport TSFN delivery hardening to v1

[Brooooooklyn]

Summary

Backport the production TSFN delivery, retirement, memory-view, and context-lifecycle hardening from #220 to the maintained v1.x line.

Scope

• generation-scoped TSFN delivery and retirement across workers;
• ambiguous transport/retry ownership and bounded reclamation;
• scheduler, worker-loss, cleanup-hook, and teardown hardening;
• refreshed shared/unshared WebAssembly memory views after reentrancy and allocation growth;
• non-spoofable shared-memory brand detection without requiring a local SharedArrayBuffer constructor;
• configurable context autoDestroy;
• MessageChannel-independent Node keepalive with paired timer cancellation;
• exception- and reentrancy-safe host ref/unref/timer handling;
• focused adversarial TSFN, generated-library, Buffer allocation-growth, and Context regression coverage.

Stack status

• Base: v1.x at 061ae9e8c0b4ec4a31db9cbaecc82a63527ad334
• Head: e61b7d4
• Draft PR; no reviewer notifications requested.
• Main-line equivalent: fix: harden emnapi v2 memory, threads, and WASI packaging #220 at a5df035a1cc2da22e8839aba8f13657970a0d9cb.

Verification

Passed locally on July 8, 2026:

• npm run build:main
• npm run build:core
• npm run build:runtime
• npm run build:node
• runtime Context suite: 19/19
• focused TSFN backport and threaded delivery tests
• Buffer allocation-growth regression
• changed-file ESLint
• git diff --check

The v2-only V8/plugin files and v8_memory_growth.test.js do not exist on v1.x; equivalent memory-growth and host-lifecycle coverage is adapted to the v1 CommonJS/context layout.

Related

• Main-line hardening: fix: harden emnapi v2 memory, threads, and WASI packaging #220
• Rolldown tracking: infra: attempt to remove tokio rolldown/rolldown#9464