Fixes to support Firmware TPM swtpm transport server on Windows

[dgarske]

Description

The socket transport has not worked on Windows. wolfTPM_tcpContext.fd is an int, while a Winsock SOCKET is an unsigned pointer-width handle and is not a C runtime file descriptor.

• tcpCtx.fd is uintptr_t on Windows. The fd < 0 guards, which cannot fire on an unsigned type, now use an invalid-socket sentinel.
• read(), write() and close() do not accept a SOCKET. The transport uses recv, send and closesocket there; UART mode keeps the POSIX calls.
• SwTpmConnect() called getaddrinfo() before WSAStartup().
• setsockopt() was passed void* where Winsock declares const char*.
• FWTPM_IO_ServerLoop() held socket handles in int maxFd, and four connection handlers took int clientFd.
• SOCKET_INVALID was 0xFFFFFFFF, which matches no socket on a 64 bit build.

Non-Windows builds generate identical code.

Hardware / test status

Linux x86-64: TLS 1.3 handshake against the firmware TPM, ML-KEM-768 key exchange, ML-DSA-65 identity held in the TPM.
Windows x64, MSYS2, mingw-w64 gcc 13.2.0, -Werror on: same handshake completes; previously the transport could not connect at all.

[Copilot]

Copilot review overview

🟢 Approval recommended

The socket-width, lifecycle, API, and platform-specific changes are consistent and covered by an end-to-end Windows workflow.

Review effort: Balanced
Findings: None

What changed in this PR

Fixes Windows socket-handle compatibility for swtpm transport and adds end-to-end Windows coverage.

Changes:

• Uses pointer-width socket types, correct invalid sentinels, and Winsock APIs.
• Corrects fwTPM server and TLS example socket handling.
• Adds a Windows MSYS2 transport test.

File	Description
wolftpm/​tpm2.h	Widens Windows socket storage.
wolftpm/​tpm2_socket.h	Defines portable invalid-socket handling.
src/​tpm2_swtpm.c	Adds correct Winsock initialization and I/O.
src/​fwtpm/​fwtpm_io.c	Preserves Windows socket width in server paths.
examples/​tls/​tls_server.c	Initializes sockets with the portable sentinel.
examples/​tls/​tls_common.h	Uses portable socket validity checks.
examples/​tls/​tls_client.c	Initializes sockets with the portable sentinel.
.github/​workflows/​win-swtpm-test.yml	Adds Windows swtpm integration coverage.

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