Activate Bun describe naming corpus

Track the next focused Bun compatibility tranche from #66.

Scope:

• activate the byte-identical upstream js/bun/test/describe.test.ts corpus under Home
• preserve number, string, named-function, named-class, and inferred anonymous-class suite names
• verify named callback behavior and anonymous-function overload validation
• retain Bun-compatible child CLI labels and pass/fail diagnostics
• add permanent Home regression coverage and run the full home_test gate

Baseline after removing the stale native-TODO gate is already 13/13 passing; this issue records and protects that capability.

Completed in a7cceb4 (test: activate describe naming corpus). The stale native-TODO gate is removed and the byte-identical upstream describe.test.ts now runs permanently under Home, passing all 13 assertions. Coverage includes number/string suites, named functions, named and inferred anonymous classes, named callbacks, child CLI labels, and invalid anonymous-function overload diagnostics. Validation passed: exact corpus 13/13, focused regression, upstream byte comparison, formatter/diff checks, and full home_test (1092 tests, 1 expected skip, 0 failures).