fix: init scripts not executable, add autologin and build version in motd

- bee-* init.d scripts had mode 644 in git — OpenRC silently skipped them,
  causing bee-network/bee-nvidia/bee-audit to never start at boot
- bee-network.sh also lacked executable bit
- Remove -q from udhcpc (was quitting after first lease, no renewal)
- Add autologin root on tty1 via /etc/inittab
- Inject build date + git commit + versions into motd at build time

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/overlay-debug/etc/inittab

@@ -0,0 +1,13 @@
+::sysinit:/sbin/openrc sysinit
+::sysinit:/sbin/openrc boot
+::wait:/sbin/openrc default
+
+# Autologin on tty1
+tty1::respawn:/sbin/getty -a root 38400 tty1
+tty2::respawn:/sbin/getty 38400 tty2
+tty3::respawn:/sbin/getty 38400 tty3
+
+ttyS0::respawn:/sbin/getty -L 115200 ttyS0 vt100
+
+::ctrlaltdel:/sbin/reboot
+::shutdown:/sbin/openrc shutdown