fix(iso): restore console=tty0 — VGA screen was black without it

Commit d36e844 dropped console=tty0 and added dual-serial + debug logging.
Without console=tty0 the kernel never initialises the VGA console,
leaving the physical screen permanently blank.

- Restore console=tty0 (VGA) as primary, keep console=ttyS0 for SOL
- Drop console=ttyS1 (redundant second serial port)
- Replace loglevel=7 + journald debug flood with loglevel=3 (errors only)
  so kernel messages don't overwrite the TUI on the local screen
- Remove systemd.log_target/forward_to_console debug params

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 console=ttyS1,115200n8 loglevel=7 systemd.log_target=console systemd.journald.forward_to_console=1 systemd.journald.max_level_console=debug username=bee user-fullname=Bee modprobe.blacklist=nouveau" \
+    --bootappend-live "boot=live components console=tty0 console=ttyS0,115200n8 loglevel=3 username=bee user-fullname=Bee modprobe.blacklist=nouveau" \
     --apt-recommends false \
     "${@}"