initramfs+kernel: path anchors, helper, and init debug hook

initramfs: anchor relative paths to PROJECT_ROOT in [bash.initramfs_validate()](scripts/lib/initramfs.sh:799) and [bash.initramfs_create_cpio()](scripts/lib/initramfs.sh:688) to avoid CWD drift. Add diagnostics logs.

kernel: anchor kernel output path to PROJECT_ROOT in [bash.kernel_build_with_initramfs()](scripts/lib/kernel.sh:174) to ensure dist/vmlinuz.efi is under PROJECT_ROOT/dist.

helper: add [scripts/rebuild-after-zinit.sh](scripts/rebuild-after-zinit.sh) to incrementally rebuild after zinit/modules.conf/init changes. Default: initramfs-only (recreates cpio). Flags: --with-kernel, --refresh-container-mods, --run-tests. Uses --rebuild-from=initramfs_create when rebuilding kernel.

init: add early debug shell on kernel param initdebug=true; prefer /init-debug when present else spawn /bin/sh -l. See [config/init](config/init:1).

modules(stage1): add USB keyboard support (HID + host controllers) in [config/modules.conf](config/modules.conf:1): usbhid, hid_generic, hid, xhci/ehci/ohci/uhci.

config/init

@@ -24,6 +24,12 @@ mount -t devtmpfs devtmpfs /dev
 mkdir -p /dev/pts
 mount -t devpts devpts /dev/pts
 
+# Early debug shell if kernel parameter initdebug=true is present
+if grep -qw "initdebug=true" /proc/cmdline; then
+    echo "[+] initdebug=true detected; starting emergency shell. Type 'exit' to continue boot."
+    /bin/sh -l
+fi
+
 echo "[+] building ram filesystem"
 
 
@@ -100,19 +106,34 @@ modprobe virtio_net 2>/dev/null || true
 modprobe e1000 2>/dev/null || true
 modprobe e1000e 2>/dev/null || true
 
+echo "[+] loading USB keyboard support"
+modprobe usbcore
+modprobe ehci-hcd
+modprobe xhci-hcd
+modprobe usbhid
+modprobe evdev
+
 # Unmount init filesystems
 umount /proc 2>/dev/null || true
 umount /sys 2>/dev/null || true
 
-echo "[+] checking for debug files"
-if [ -e /init-debug ]; then
-    echo "  executing debug script..."
+echo "[+] debug hook: initdebug=true or /init-debug"
+if grep -qw "initdebug=true" /proc/cmdline; then
+    if [ -x /init-debug ]; then
+        echo "  initdebug=true: executing /init-debug ..."
+        sh /init-debug
+    else
+        echo "  initdebug=true: starting interactive shell (no /init-debug). Type 'exit' to continue."
+        /bin/sh -l
+    fi
+elif [ -x /init-debug ]; then
+    echo "  executing /init-debug ..."
     sh /init-debug
 fi
 
 echo "[+] switching root"
 mkdir /root/home
 echo "  exec switch_root /mnt/root /sbin/zinit init"
-exec switch_root /mnt/root /sbin/zinit init
+exec switch_root /mnt/root /sbin/zinit -d init
 
 ##

config/modules.conf

@@ -38,3 +38,20 @@ stage1:tun:none                         # TUN/TAP for networking
 stage1:overlay:none                     # OverlayFS for containers
 stage1:fuse:none                        # OverlayFS for containers
 
+# Stage 1: USB keyboard support (host controllers + HID)
+stage1:xhci_pci:none
+stage1:xhci_hcd:none
+stage1:ehci_pci:none
+stage1:ehci_hcd:none
+stage1:ohci_pci:none
+stage1:ohci_hcd:none
+stage1:uhci_hcd:none
+stage1:usbhid:none
+stage1:hid_generic:none
+stage1:hid:none
+stage1:atkbd:none
+stage1:libps2:none
+stage1:i2c_smbus:none
+stage1:serio:none
+stage1:i8042i:none
+