Fix garage container command and drop postStart layout hook

The dxflrs/garage image ships as a single static binary with no
ENTRYPOINT and no shell, so `args: [server]` alone was exec'd as the
command (crash loop) and the shell-based postStart layout-bootstrap
hook could never run. Set command: [/garage] explicitly, and replace
the automated hook with documented one-time `kubectl exec` steps.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014ZA4cJygj4VPCYVms4TDrH

garage/values.yaml

@@ -17,7 +17,8 @@ garage:
   replicationFactor: 1
   consistencyMode: consistent
   dbEngine: sqlite
-  # Zone/capacity used by the layout job to bootstrap a single-node cluster.
+  # Recommended zone/capacity for the one-time manual layout bootstrap
+  # (see NOTES.txt) - `garage layout assign -z <zone> -c <capacity> <node-id>`.
   zone: dc1
   capacity: 100G
   rpcBindAddr: "[::]:3901"
@@ -91,11 +92,6 @@ ingress:
     hosts: []
     tls: []
 
-# One-shot Helm hook Job that assigns and applies a single-node layout on
-# first install. Safe to re-run; it exits early once a layout already exists.
-layoutJob:
-  enabled: true
-
 resources:
   requests:
     cpu: 100m