fix(ci): address Windows test failures and timeout

- Extract inode function to platform-specific files (inode_unix.go,
  inode_windows.go) to fix syscall.Stat_t compile error on Windows
- Add skipOnWindows helper and skip Unix permission/symlink tests
  on Windows where chmod semantics differ
- Increase Windows test timeout from 10m to 20m since full test
  suite runs slower without race detector

Fixes Windows CI failures introduced when PR #904 expanded Windows
testing from smoke tests to full test suite.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/storage/sqlite/inode_windows.go

@@ -0,0 +1,9 @@
+//go:build windows
+
+package sqlite
+
+// getInode returns 0 on Windows as inodes don't exist.
+// Used for debugging file replacement detection in tests.
+func getInode(_ string) uint64 {
+	return 0
+}