feat: support IPv4/IPv6 web listener availability

[mark-e-deyoung]

Summary

• replace HTTP/HTTPS IPv4 INADDR_ANY listeners with one shared multi-address resolver/binder
• translate stable config families to native AF values, bind IPv4/IPv6 independently, preserve partial success, apply scope IDs, set IPV6_V6ONLY explicitly, and use exclusive address binding on Windows
• return accepted sockets to blocking mode, fixing the existing TLS WANT_READ handshake failure
• add --no-update-check so transport tests are hermetic
• add a required Windows HTTP/HTTPS × IPv4/IPv6 live health matrix
• model all requested/available family combinations in TLA+ and replay a versioned trace
• document current gaps and RFC 8305/6724/3986/9844/9872 guidance

Validation

• MSVC Release wininspectd and est_core: build pass
• full core CTest: pass (9.04s)
• live matrix: HTTP IPv4, HTTP IPv6, HTTPS IPv4, HTTPS IPv6 all pass
• Linux GCC strict object compile: -Wall -Wextra -Wpedantic -Werror pass
• clang-format --Werror: pass
• TLC address availability: 12 initial states, 34 generated / 33 distinct, no violations
• git diff --check`n

Scope

Advances #304 and #300. This slice covers HTTP/HTTPS listeners. TCP helper migration, TLS-TCP, clients/Happy Eyeballs, rendezvous, discovery/mDNS, link-local UI, NAT64, Windows/Wine scheduled matrices, and effective-endpoint reporting remain follow-ups.

Stacked on #305.