Remove unsupported healthcheck port from Garage accessory

Kamal does not yet support healthcheck.port (basecamp/kamal#1750).
Remove the healthcheck block until that feature is available.

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

Author: ursm

config/deploy.yml

@@ -66,11 +66,6 @@ accessories:
       app_port: 3900
       response_timeout: 600
 
-      healthcheck:
-        interval: 3
-        path: /health
-        port: 3903
-
     options:
       user: 2233:11370