docs(deploy): add install guide for a domain with HTTPS

- docs/install-guide.md: step-by-step server setup (DNS, Docker, install.sh,
  .env, launch, checks), web and Android client setup, own reverse proxy
  variant, updates, backups and troubleshooting
- deploy/compose.tls.yaml + Caddyfile: optional Caddy with automatic
  Let's Encrypt in front of nginx (enabled via COMPOSE_FILE in .env)
- nginx: honour X-Forwarded-Proto/For from private networks
- .env.example: DOMAIN, ACME_EMAIL, COMPOSE_FILE, bootstrap admin vars
- install.sh: create caddy data dirs; release.yml: ship TLS files as assets
- deployment.md, docs index and README link to the guide

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -159,7 +159,7 @@ jobs:
             '{tag_name:$tag, name:$name, body:$notes, prerelease:$pre, draft:false}')"
           id="$(curl -fsS -X POST -H "Authorization: token $TOKEN" -H 'Content-Type: application/json' \
             -d "$body" "$API/releases" | jq -r .id)"
-          for f in "$APK" "$APK.sha256" deploy/compose.yaml deploy/.env.example deploy/install.sh deploy/update.sh; do
+          for f in "$APK" "$APK.sha256" deploy/compose.yaml deploy/compose.tls.yaml deploy/Caddyfile deploy/.env.example deploy/install.sh deploy/update.sh; do
             curl -fsS -X POST -H "Authorization: token $TOKEN" \
               -F "attachment=@$f" "$API/releases/$id/assets?name=$(basename "$f")" > /dev/null
             echo "uploaded $(basename "$f")"