Activate Bun internal source-map stack-trace integration corpus

Port the adjacent byte-identical Bun js/bun/sourcemap/internal-sourcemap.test.ts corpus into honest Home coverage.

Current evidence:

• upstream Bun file and Home corpus copy have identical SHA-1
• unmodified file already passes under Home full VM: 4 pass, 0 fail, 32 assertions
• normal corpus routing currently rewrites the file to a native TODO

Acceptance:

• remove the TODO rewrite
• route this service-dependent file through the full native VM
• exact checked-in corpus path reports 4 pass / 0 fail / 32 assertions
• debug build and full home_test gate pass
• commit and push directly to main as Chris Breuer, then update #66

Completed in d3b568f.

The checked-in corpus is byte-identical to Bun upstream and now runs honestly through Home full-VM routing instead of being rewritten to a TODO.

Acceptance evidence:

• exact internal-sourcemap.test.ts: 4 pass, 0 fail, 32 assertions
• covers thrown errors, new Error().stack, captureStackTrace, very long generated lines, multiple sync points, and >16-window FindCache eviction
• zig build debug --summary failures: pass
• zig build test -Dfilter=home_test --summary failures: pass

The broader Bun parity goal continues in #66.