Caddy routes the duel server's paths with handle blocks, from one template

try_files ran before reverse_proxy and rewrote /api to the shell; handle
blocks are exclusive. Both setup scripts render deploy/Caddyfile.tmpl.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

deploy/setup-server.sh

@@ -1,8 +1,9 @@
 #!/usr/bin/env bash
 # Adds the duel server to a droplet that setup-droplet.sh already prepared.
-# Run ON the droplet as root; safe to run again. Installs Node 22, creates
-# the service user and data directory, and teaches Caddy to hand /api and
-# /ws to the server while it keeps serving the static site itself.
+# Copy this script and Caddyfile.tmpl to the droplet and run ON the droplet
+# as root; safe to run again. Installs Node 22, creates the service user and
+# data directory, and teaches Caddy to hand /api and /ws to the server while
+# it keeps serving the static site itself.
 set -euo pipefail
 
 if ! command -v node >/dev/null || [[ "$(node -v)" != v22* ]]; then
@@ -14,24 +15,11 @@ id -u waving-hands &>/dev/null || useradd -r -m -d /opt/waving-hands-home waving
 mkdir -p /opt/waving-hands/app /var/lib/waving-hands/rooms
 chown -R waving-hands:waving-hands /var/lib/waving-hands
 
-# Caddy: the two proxied paths go in before the static file handling.
-if ! grep -q 'reverse_proxy' /etc/caddy/Caddyfile; then
-  python3 - <<'PY'
-import pathlib
-p = pathlib.Path('/etc/caddy/Caddyfile'); s = p.read_text()
-marker = 'try_files {path} {path}.html /index.html'
-proxy = '''@duel path /api/* /ws
-reverse_proxy @duel localhost:8788 {
-	lb_try_duration 30s
-	lb_try_interval 250ms
-}
-
-'''
-assert marker in s
-p.write_text(s.replace(marker, proxy + marker))
-PY
-  caddy validate --config /etc/caddy/Caddyfile
-  systemctl reload caddy
-fi
+# Caddy: rewrite the site's configuration from the template, keeping its
+# address line, so the duel server's paths are routed before the files.
+HOST_LINE=$(head -1 /etc/caddy/Caddyfile)
+sed "s|__HOST__|$HOST_LINE|" "$(dirname "$0")/Caddyfile.tmpl" > /etc/caddy/Caddyfile
+caddy validate --config /etc/caddy/Caddyfile
+systemctl reload caddy
 
 echo "server prerequisites ready: now run deploy/deploy.sh <ip> from your machine"