fix: remove serial console (root cause of 30s boot delay), enable syslog logging, disk auto-detect

Root cause found: console=ttyS0,115200n8 causes 30-second timeout at every
systemd boot phase on hardware without a physical serial UART. Each phase
transition blocks waiting for the non-existent UART.

Changes:
- Remove console=ttyS0 from kickstart bootloader args and %post setup
- Enable Anaconda syslog forwarding (logging --host --port) for install visibility
- Improve syslog IP→MAC resolution (register from kickstart fetch + progress)
- Fix disk auto-detect: default to empty string (not /dev/sda) for NVMe support
- Enable SysRq magic keys (kernel.sysrq=1) for emergency reboot via JetKVM
- Simplify debug command: remove --sshd flag (inst.sshd always available),
  add /debug-setup.sh HTTP endpoint for nc listener setup
- Add labctl provision logs -f (follow mode with polling)
- Add syslog listener unit tests
- Enable syslog log capture test in integration suite

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

bastion/completions/labctl.bash

@@ -62,13 +62,13 @@ _labctl() {
       COMPREPLY=($(compgen -W "--role --os --disk -h --help" -- "$cur"))
       return ;;
     "provision debug")
-      COMPREPLY=($(compgen -W "--sshd -h --help" -- "$cur"))
+      COMPREPLY=($(compgen -W "--pxe-boot -h --help" -- "$cur"))
       return ;;
     "provision forget")
       COMPREPLY=($(compgen -W "-h --help" -- "$cur"))
       return ;;
     "provision logs")
-      COMPREPLY=($(compgen -W "-h --help" -- "$cur"))
+      COMPREPLY=($(compgen -W "-f --follow -h --help" -- "$cur"))
       return ;;
     "provision makeiso")
       COMPREPLY=($(compgen -W "--arch --local --out -h --help" -- "$cur"))