fix(boot): fix black screen on monitor, stop log spam on console

- Add console=tty0 so VGA display gets kernel output (was serial-only)
- Change loglevel=7→3 (debug→errors only)
- Add quiet to suppress verbose kernel boot messages
- journald: ForwardToConsole=no so service logs don't flood tty1

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

iso/builder/auto/config

@@ -32,6 +32,6 @@ lb config noauto \
     --memtest none \
     --iso-volume "EASY-BEE" \
     --iso-application "EASY-BEE" \
-    --bootappend-live "boot=live components console=ttyS0,115200n8 loglevel=7 username=bee user-fullname=Bee modprobe.blacklist=nouveau" \
+    --bootappend-live "boot=live components quiet console=tty0 console=ttyS0,115200n8 loglevel=3 username=bee user-fullname=Bee modprobe.blacklist=nouveau" \
     --apt-recommends false \
     "${@}"