fix: gitea boot persistence via quadlet (incident 2026-08-16)

unattended-upgrades rebooted dankclaw at 15:01; the legacy
podman-compose gitea stack had no systemd units, so rootless podman
did not auto-start the containers. Gitea was down ~1 hour.

- add quadlet units (dankclaw/gitea/quadlet/): gitea-postgres,
  gitea-server, gitea-caddy + gitea.network (DNS enabled; the default
  rootless podman network has dns_enabled=false)
- add gitea stack Caddyfile (upstream gitea-server:3000) and
  .env.example; live password stays in /opt/gitea/.env (0600)
- fix latent name bugs in main stack config: DATABASE_HOST
  gitea-postgres, Caddyfile upstream gitea-server
- docs: rewrite Gitea page for the quadlet stack (management, boot
  persistence, secrets, gotchas, incident log); fix port 3000 in
  stack table; Postgres connection notes
- legacy compose retired on target to /opt/gitea/.deprecated/

dankclaw/gitea/quadlet/gitea-caddy.container

@@ -0,0 +1,31 @@
+# Quadlet unit: Gitea Caddy reverse proxy (rootless, boot-persistent).
+#
+# Install path on dankclaw: ~/.config/containers/systemd/gitea-caddy.container
+# Unit name: gitea-caddy.service (podman 5.x drops the container- prefix)
+#
+# Serves gitea.franksdank.cloud (public domain, DNS pending). The LAN
+# reaches Gitea directly on port 3000. This file holds no secrets.
+# See docs/Dankclaw/Gitea.md.
+
+[Unit]
+Description=Gitea Caddy reverse proxy container
+Wants=gitea-server.service
+After=gitea-server.service network.target
+
+[Container]
+ContainerName=gitea-caddy
+Network=gitea.network
+Image=docker.io/library/caddy:latest
+PublishPort=80:80
+PublishPort=443:443
+Volume=/opt/gitea/data/caddy/Caddyfile:/etc/caddy/Caddyfile
+Volume=/opt/gitea/data/caddy/site:/srv
+Volume=/opt/gitea/data/caddy/config:/config
+Volume=/opt/gitea/data/caddy/data:/root/.local/share/caddy
+
+[Service]
+TimeoutStartSec=900
+Restart=always
+
+[Install]
+WantedBy=default.target