Switch to HWE kernel and improve boot reliability

- Install linux-image-generic-hwe-24.04 (6.14+) for RTL8125BP XID 689 support
- Enable noble-updates and noble-security repositories in chroot
- Add explicit rdinit=/init and panic=-1 kernel parameters for boot robustness
- Rename CLAUDE.md to AGENTS.md for broader AI assistant coverage
- Document dracut module alternative and verify-image.sh utility
- Clean up initramfs netboot script comments

initramfs/scripts/netboot

@@ -1,7 +1,5 @@
 #!/bin/sh
-
-# Import standard initramfs functions
-. /scripts/functions
+# Netboot HTTP root mounting - sourced by initramfs init (functions already loaded)
 
 export PATH=/usr/bin:/usr/sbin:/bin:/sbin
 MOUNTPOINT=/root