Port Bun failure-skip hook scheduling matrix

Track the next focused Bun compatibility tranche from #66.

Scope:

• run the byte-identical upstream js/bun/test/failure-skip.test.ts corpus under Home
• preserve Bun hook-failure scheduling semantics across beforeAll, beforeEach, tests, afterEach, and afterAll
• cover environment-selected failure points in spawned test fixtures
• add a permanent Home regression and run the full home_test gate

This issue will be closed by the direct-main implementation commit.

Completed in 235fdd0 (feat(test): port failure skip scheduling). The byte-identical upstream failure-skip.test.ts now passes all 11 cases under Home. The spawned fixture models Bun hook scheduling for beforeAll, beforeEach, test bodies, afterEach, and afterAll, including teardown behavior after setup failures. Added a permanent aggregate regression. Validation passed: exact corpus 11/11, focused regression, formatter and diff checks, upstream byte comparisons, and full home_test (1085 tests, 1 expected skip, 0 failures).