fix: dropbear/network boot ordering — dropbear starts without network

- dropbear: custom init removes 'need net', only needs localmount + bee-sshsetup
- bee-network: removed 'before dropbear' dependency
- bee-network.sh: removed set -e so single iface failure does not abort script

iso/overlay-debug/usr/local/bin/bee-network.sh

@@ -2,8 +2,6 @@
 # bee-network.sh — bring up all physical network interfaces via DHCP
 # Unattended: runs silently, logs results, never blocks.
 
-set -e
-
 LOG_PREFIX="bee-network"
 
 log() { echo "[$LOG_PREFIX] $*"; }