Fix Windows release CRT dependency

[chenyukang]

Fixes #1344.

Summary

• Build Windows release binaries with the MSVC CRT statically linked by switching the vcpkg OpenSSL triplet from x64-windows-static-md to x64-windows-static and setting RUSTFLAGS=-C target-feature=+crt-static.
• Mirror the same static-CRT configuration in the Windows CI build so the release path is continuously covered.
• Add a Windows store-open smoke test that runs fnn.exe --check-validate against an empty store, catching process crashes before packaging a release.

Root Cause

The Windows release workflow built on windows-2022 with openssl:x64-windows-static-md and Rust MSVC defaults. That combination statically linked OpenSSL but dynamically linked the MSVC C runtime, so fnn.exe depended on a sufficiently new system-wide MSVCP140.dll / VCRUNTIME140.dll. On machines with older VC++ Redistributable versions, the binary could crash with 0xC0000005 when startup first opened RocksDB.

Validation

• rtk git diff --check upstream/develop...HEAD
• rtk ruby -e 'require "yaml"; YAML.load_file(".github/workflows/release.yml"); YAML.load_file(".github/workflows/ci.yml"); puts "yaml ok"'
• Local smoke command using target/debug/fnn --check-validate against an empty store, confirming the command reaches the database validation path and returns a Rust-level validation error instead of failing before store open.

Release test triggers

#windows-release-test

[chenyukang]

Windows release test binary is available from the CI run:

• Artifact: fnn-pr1537-x86_64-windows
• Run: https://github.com/nervosnetwork/fiber/actions/runs/28860455765
• Commit: 2463c4d54263036dbb826726019c98d0bccdf32f
• SHA256 of fnn_pr1537_x86_64-windows.tar.gz: 5be6c8f053f4c5ab0eec657668956be982fe6b440e5f0cfe7c0384b3efd08cee

The package contains fnn.exe, fnn-cli.exe, and config/.