Add Windows native watcher with Unix socket IPC

Architecture:
- Windows binary: watches files via ReadDirectoryChangesW (fsnotify),
  sends events as newline-delimited JSON over Unix domain socket
- Container: performs initial sync, then listens on socket for events
  from Windows watcher

New files:
- cmd_windows.go: Windows serve command (watcher + socket server)
- cmd_linux.go: Linux socket client + event listener
- types.go: shared FileEvent, FileMeta, Manifest types
- watcher_test_helper.go: inotify-based watcher for integration tests

Changes:
- main.go: simplified to just call run()
- watcher.go: removed fsnotify dependency, extracted Watcher interface
- sync.go: removed duplicate type definitions
- watcher_test.go: uses watchForTests() helper

Usage:
  sourcewatch.exe -dir C:\myproject -socket D:\sourcewatch.sock
  docker run -v D:\sourcewatch.sock:/run/sourcewatch.sock \
             -v C:\myproject:/host:ro -v mydata:/data sourcewatch

0 files changed, 0 insertions, 0 deletions