fix(node:net): validate listen ports synchronously

[steipete]

http.Server.listen(65536) and https.Server.listen(65536) now throw RangeError with ERR_SOCKET_BAD_PORT before returning, matching Node 24. Real bind failures such as EADDRINUSE still arrive through the asynchronous error event.

HTTP previously validated inside Bun.serve() and caught argument errors as bind failures. This moves port validation ahead of DNS/binding, uses full numeric-string conversion instead of parseInt, and preserves TCP-port precedence over a simultaneous path. The net change keeps empty strings intact until validation and uses Node's pipe-name routing. Numeric, string, options, host, backlog, non-integer, negative, non-finite, and whitespace cases are covered across net/HTTP/HTTPS.

Adapts the net string-routing and U+3000 whitespace fixes from oven-sh/bun#34083, which remains open. The HTTP/HTTPS timing fix is additional. Thanks @robobun. No upstream HTTP timing fix was found in the scoped search.

Validation used a dedicated Linux host and Node v24.19.0:

• Dependency-free oracle: all 264 invalid-port cases plus three asynchronous EADDRINUSE controls pass after the fix; c999 and unpatched fork main each mismatch 195 cases.
• New regression suite: c999 has 36 failures and 39 passes; patched head passes all 75 tests.
• Surrounding node-net-server.test.ts, node-http.test.ts, and node-tls-server.test.ts pass with --expose-internals, as required for release-build test internals.
• OpenClaw src/gateway/server/http-listen.test.ts, pinned to affb994cf4193ff967b0f792b4634435d3942948: Node 5/5, c999 4/5, patched 5/5. Bun runs use OPENCLAW_VITEST_RUNTIME=bun, private HOME/state/TMPDIR, and umask 022.
• Scoped P2 branch review is clean. Linux x64 and macOS arm64 CI both passed on exact head c75c48109ac294dbe78e2f2bbf8cd2ddaea65f31; format and JavaScript lint also passed. The optional Claude workflow fails at credential validation before analysis (existing fork setup issue).

The fork changelog is append-only and the Node compatibility notes describe the new error timing.