Fixed seam issues found during cross-series verification:
- Add path traversal guard to DownloadAgent signed-package path
- Replace fmt.Printf DEBUG/Warning in updates.go with log.Printf
- Replace 11 emoji in subsystem_handlers.go daemon logs with ETHOS format
All series verified to work together correctly.
170 tests pass. Full ETHOS compliance confirmed.
3 cross-platform builds pass (linux-amd64, linux-arm64, windows-amd64).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
