Port HTTP/1.1 chunked transfer TCP corpus

Focused Bun parity tranche split from #66.

Current state:

• js/bun/http/http-server-chunking.test.ts is byte-identical to ~/Code/bun
• Home currently rewrites the complete file to one native TODO

Scope:

• activate fragmented chunk terminator handling
• activate split chunk-size CRLF and extension handling
• reject bare LF, invalid terminators, zero-digit sizes, and oversized Content-Length state aliasing
• preserve request-smuggling protections for trailing pipelined requests
• cover tiny TCP send-buffer behavior
• keep the upstream fixture untouched and add a permanent Home regression

Acceptance:

• exact fixture passes with zero failures/TODOs/unsupported cases
• adjacent HTTP parser corpora remain green
• complete home_test gate passes

Completed and pushed to main in b104516ce.

What landed:

• activated the untouched js/bun/http/http-server-chunking.test.ts corpus
• added test.concurrentIf / it.concurrentIf compatibility
• implemented socket send/receive option handling used by the tiny-buffer cases
• replaced the one-request bridge with persistent sequential HTTP/1.1 request processing
• buffered fragmented chunk-size lines and chunk terminators
• parsed chunk extensions and validated hexadecimal sizes and CRLF framing
• rejected malformed framing with HTTP 400 plus deterministic connection close
• preserved ordered pipelined responses and HTTP/1.1 keep-alive / explicit close behavior
• added a durable exact-corpus Home regression

Verification:

• exact upstream corpus: 11 passed, 0 failed, 0 unsupported, 0 TODO
• focused matrix including adjacent HTTP/server/header corpora: 118 active passed, 0 failed, 0 unsupported, with 2 explicit upstream TODOs in bun-serve-file
• bun-serve-static.test.ts: 34/34 passed
• complete home_test gate: exit 0 in 19m39.84s
• Home and ~/Code/bun fixture SHA-256 match: fb092606e46ef5f1e331fe1a6358e9836f9c187d69e0e1a48f842dc98a0bea00

No upstream corpus files were modified.