fix(compose): pin auth./pack. to host-gateway so HTTPS resolves in-container

Containers don't inherit the host's /etc/hosts; the LAN resolver returns a
dead address (192.168.0.3:443) for the public names, crash-looping the
packwiz install on boot. extra_hosts host-gateway routes HTTPS through the
host's nginx (valid LE cert) -> caddy -> service.

Also add plan/10-uptime-kuma.md (Minecraft monitor: internal + public probes)
and document the HTTPS resolution variant in plan/00-overview.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -86,6 +86,12 @@ services:
     depends_on:
       - drasl
       - caddy                      # pack./auth. must resolve at boot
+    # Containers don't inherit the host's /etc/hosts; the LAN resolver returns a
+    # dead address for the public names. Pin auth./pack. to the host so HTTPS to
+    # them lands on the host's nginx (valid LE cert) -> caddy -> service.
+    extra_hosts:
+      - "auth.${BASE_DOMAIN}:host-gateway"
+      - "pack.${BASE_DOMAIN}:host-gateway"
     networks:
       - mcnet