wg-quick's own AllowedIPs route handling does a plain `ip route add`
per entry into the main table and hard-fails the whole interface
bring-up with "RTNETLINK: File exists" the moment two servers share
an overlapping AllowedIPs entry (real case: a client's transit IP
duplicated across 4 imported servers). Set Table = off and generate
`ip route replace` PostUp commands instead - idempotent, never fails
on a pre-existing route, and multiple servers can coexist even when
their peers' AllowedIPs overlap.
Also make ServerServiceRestart write the config to disk first, same
as ServerServiceStart already does - it had the same "config file
missing" failure mode.
sysops
cf9c136874