Port S3 insecure HTTP endpoint read errors

Scope

Activate and pass js/bun/s3/s3-insecure.test.ts from the copied Bun corpus.

Required behavior

• Implement S3Client.file() read methods through the Home S3/HTTP compatibility layer.
• Preserve plain http:// endpoints instead of forcing TLS or failing to connect.
• Route local requests through the active Home Bun.serve dispatcher.
• Translate non-success HTTP responses into S3-layer errors with Bun-compatible code: "UnknownError".
• Add an exact-corpus repository regression and pass the full Home test gate.

Follows #94 and tracks another bounded S3 tranche of #66/#81.

Implemented and published on main in 3a850e7494ea4f9432465a623c31606fc0f433fa (feat(test): port S3 insecure endpoint reads).

What landed:

• S3Client.file() text/JSON/ArrayBuffer reads through the Home S3 endpoint path
• object-key and bucket URL encoding without changing an explicit http:// endpoint
• dispatch through an active local Bun.serve handle
• non-success HTTP responses translated to S3 errors with code: "UnknownError" and status metadata
• activation and permanent exact-corpus coverage for s3-insecure.test.ts

Verification:

• exact current fixture: 1 pass, 0 fail/todo/unsupported
• full home_test gate: passed with zero failures.