Replace the no-op Windows lock stub with actual kernel32 LockFileEx /
UnlockFileEx calls via syscall.LazyDLL (zero external dependency).
- LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY for non-blocking
semantics matching Clipper FLOCK() → .F.
- Same lock region layout as POSIX: header region for FLOCK, record
offsets for DBRLOCK — compatible across platforms
- Handles returned as syscall.Handle from os.File.Fd()
Note: full Windows cross-compile still blocked by unrelated issues
(mmap in cdx/ntx, termios in debugcli.go). The lock code itself
compiles cleanly with //go:build windows.
Also updates gap-analysis.md to reflect Windows lock status.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
CharlesKWON
3ed246c47e