fix(http): make Agent/ClientRequest/IncomingMessage/ServerResponse constructable via new (#4904)

[proggeramlug]

Summary

Fixes #4904 — Node exposes http.Agent, http.ClientRequest, http.IncomingMessage, and http.ServerResponse as constructable classes; under Perry, new-ing them threw TypeError: <X> is not a constructor through every value-aliasing path (const { Agent } = require('http'), require('_http_agent').Agent, const CR = http.ClientRequest, new http.IncomingMessage(), …).

Mechanism (mirrors the existing OutgoingMessage route end-to-end)

• runtime/native_module — export the four classes as bound callable values with Node .length arities, plus the previously missing http.get / http.request value exports (the https twins already existed; const { Agent, get } = require('http') destructuring needs both).
• runtime/class_registry — extend the http construct arm so js_new_function_construct forwards (module, class, args) through JS_NATIVE_HTTP_DISPATCH; the real module name is forwarded so https.Agent constructs with the https protocol default.
• stdlib/dispatch — constructor arms: Agent → js_http_agent_new, ClientRequest → new js_http_client_request_standalone_new (defers the send to .end(), matching Perry's client model), IncomingMessage / ServerResponse → new standalone factories in perry-ext-http-server; plus get/request value-call arms.
• HIR — member-form new http.{ClientRequest,IncomingMessage,ServerResponse}() joins the OutgoingMessage NewDynamic route; bare-ident forms (destructured imports) added for all four; the three handle-backed classes are skip-listed from typed native-instance registration so instances dispatch dynamically via HANDLE_*_DISPATCH.
• cjs_wrap — require('_http_agent') (and the other _http_* internal modules) binds its hoisted import to the public http surface.

Instance surface

• IncomingMessage: standalone ctor stores the socket argument verbatim; socket/connection get/set aliasing (Node's connection accessor writes this.socket); _addHeaderLine with Node's matchKnownFields semantics (first-wins singles, ', '/'; ' joins, set-cookie array).
• ServerResponse: standalone ctor (captures req.method; HEAD suppresses the body), assignSocket/detachSocket with ERR_HTTP_SOCKET_ASSIGNED on double assignment, write(chunk, cb) callback queueing, end() flushes head+body through the assigned socket's JS write (one corked write + the zero-length finish chunk Node emits), write/end callbacks invoked in order.
• Agent: dynamic property reads (maxSockets, freeSockets, protocol, …) and writes (tunables + createConnection/createSocket monkeypatching) through handle dispatch in both perry-stdlib and perry-ext-http.

Drive-by SIGSEGV fix

json/stringify.rs's is_closure_value probed CLOSURE_MAGIC at offset 12 of POINTER_TAG payloads without the handle-band guard (same #2154 bug class as the sibling probe at line ~1106), so JSON.stringify of { agent, lookup: () => {} } dereferenced unmapped low memory and crashed http.get({ agent: new Agent({ timeout: 50 }), lookup: () => {} }). Now routes through addr_class::is_handle_band first.

Validation

• Issue's 13 Node corpus tests (pinned v22 test/parallel): 7 now pass outright — client-defaults, agent-timeout-option, client-timeout-option-with-agent, incoming-message-connection-setter, incoming-message-destroy, outgoing-message-write-callback, server-response-standalone (was 0/13; all 13 previously died at construction). The other 6 construct and run to their assertions:
  • agent-keepalive, agent-keepalive-delay, agent-error-on-idle, agent-abort-controller, client-set-timeout-after-end need real Agent pool emulation (per-key sockets/freeSockets arrays, pool-driven createConnection with live socket objects) — Agent-pool follow-up territory (node:http: missing server/timer/socket lifecycle methods (closeAllConnections, setTimeout, timer.unref, ...) #4905/node:http/https: 89 tests exit non-zero with no output (triage; likely server-hang/framing, partly cascades from #4903) #4909 family).
  • incoming-matchKnownFields hits a pre-existing assert.deepStrictEqual divergence: const d = {}; d.x = 'v' never compares equal to { x: 'v' } (reproduces without any http involvement). Will file separately.
• Curated node-suite: http 18/18, https 5/5 — 100%, 0 regressions.
• Crate tests: perry-ext-http-server / perry-ext-http / perry-runtime / perry-stdlib / perry-hir / perry(--lib) all green; new unit tests for matchKnownFields classification and the socket-alias assignment.
• Gates: cargo fmt --check, file-size gate, GC store-site inventory, addr-class inventory all pass.

Version bump + changelog left for merge time per the maintainer-folds-metadata flow.

Part of #2132.