Run client stacks under simulation

[dhruvl]

aiohttp's client and httpx now complete real requests under a SimLoop; both compatibility rows flip to works, probe-verified.

• Stream transports answer get_extra_info("socket") with a stand-in socket: synthetic-IP address tuples, inert option calls, and a fileno() backed by a parked descriptor pair whose readability mirrors the peer's EOF — so httpcore's liveness poll keeps pooled connections alive exactly while the simulated connection is. A reset or teardown reads as -1. Descriptors are reclaimed with the transport and at loop close.
• sock_connect accepts AF_INET stream sockets: it vets the address shape, resolves the target against the host table, and parks it; create_connection(sock=...) claims the entry, closes the real descriptor, and runs the ordinary simulated handshake, so the upgrade pays the same round trip a direct connect pays and refusal surfaces the same way. Datagram and raw variants still fence.
• A resolver pin keeps getaddrinfo at one row per socket kind, which is what keeps both stacks' happy-eyeballs machinery dormant.
• Docs tell the measured story: refreshed compatibility table and prose, the supported-api contract for the new surface, and a TLS section scoped to what was actually observed - aiohttp fences on create_connection(ssl=...), httpx drives an in-process handshake that reaches no fence and times out against a plaintext peer.

Suite green including a determinism case that drives the whole client path; no new runtime dependencies; ResourceWarning footprint identical to main.