Replace builder droplets stuck provisioning (#864)

A droplet DigitalOcean still reports as "new" never registers a runner, but
the controller counted it as one booting and created no replacement until
MAX_AGE_MINUTES. A publish job sat queued for minutes behind one in mkc1.

Delete droplets still provisioning after MAX_BOOT_MINUTES (10) and leave them
out of the live count, so the same tick creates a replacement.

ci/controller-box/controller.env.example

@@ -11,6 +11,8 @@ SIZES="g5-32vcpu-64gb-50gb g5-32vcpu-128gb-50gb"
 REGIONS=
 MAX_DROPLETS=6
 MAX_AGE_MINUTES=200
+# Delete a droplet DigitalOcean still reports as provisioning after this long.
+MAX_BOOT_MINUTES=10
 LOCK=/run/omarchy-controller/lock
 # Operator public keys for root on every builder droplet (JSON array).
 # create.sh fills this from the operators' GitHub keys.