fix: RunRemote SSH-to-source with pre-installed dest key, eliminating base64 round-trip

- Regenerate qnap.key and baby-nas.key to OpenSSH native format (387 bytes vs 119 PKCS8)
- Pre-install qnap.key on Baby NAS at /var/lib/syncserver/ssh/keys/
- Pre-populate Baby NAS known_hosts with Qnap host keys
- Simplify RunRemote: LXC SSH to Baby NAS, Baby NAS runs rsync with local qnap.key
- Remove wrapper script approach (rsync rejects remote-to-remote)

cmd/server/main.go

@@ -20,7 +20,7 @@ import (
 	"github.com/syncserver/internal/syncengine"
 )
 
-var version = "1.0.27"
+var version = "1.0.28"
 
 func main() {
 	cfgPath := flag.String("config", "", "Path to config.yaml")