feat: enable Asio SSL and libmysqlclient on Windows

[wellwei]

Summary

• enable the existing asio-ssl consumer on Windows and make an unwired feature fail at compile time instead of passing as a no-op
• publish the existing immutable compat.libmysqlclient 8.4.6 and 8.4.6.1 archives for Windows, with a real ABI/runtime-handle consumer assertion
• record the implementation and validation boundaries for the OpenSSL Windows follow-ups

Scope

• included: Asio SSL and libmysqlclient Windows coverage
• deferred: MySQL Connector/C++ Windows hook design and gRPC
• no package source bytes, URLs, or SHA-256 identities were changed

Local validation

• Lua syntax, mirror URL, package-name, cross-package-reference, and platform-version-parity checks passed
• workflow-pinned mcpp 2026.8.10.3 parsed all 98 descriptors
• cold macOS consumer tests passed with both mcpp 2026.8.10.3 and the authoritative latest release 2026.8.17.1
  • asio-ssl: real loopback TLS handshake passed
  • libmysqlclient: ABI/version and non-null mysql_init handle assertions passed
• both libmysqlclient archives were downloaded again; SHA-256 matched the existing descriptor values and both contain the Windows source/define/system-library recipe

Windows validation boundary

Wine 11.14 with the verified mcpp 2026.8.17.1 Windows asset reaches the Windows compat.openssl install hook, but the simulated MSVC wrapper stalls during OpenSSL's compiler probe. That is a local Wine limitation, not a Windows pass. Native GitHub Actions Windows jobs are required to establish compile, link, and runtime support.