feat(services): HTTP/2 + HTTP/3 support via Caddy reverse-proxy

Swap Werkzeug for Caddy as the protocol layer for http and https decoy
services. Flask keeps owning app logic (fake_app, custom_body, headers,
syslog) on 127.0.0.1:8080; Caddy terminates h1/h2/h2c/h3 on the wire
with real-world TLS/QUIC fingerprints.

- Add `multi_enum` FieldType to ServiceConfigField + _coerce
- Add `http_versions` field to HTTPService (h1/h2c) and HTTPSService
  (h1/h2/h3); selecting h3 emits UDP/443 port mapping in compose
- Rewrite both Dockerfiles with multi-stage Caddy binary copy +
  setcap for port binding as the logrelay user
- Entrypoints parse HTTP_VERSIONS JSON, render a Caddyfile, start
  Flask in background, wait for it, then exec Caddy
- https/server.py drops direct TLS handling; Caddy owns the cert
- Add ProxyFix to both server.py so Flask sees real attacker IPs
- Frontend: multi_enum checkbox-group renderer in ServiceConfigFields;
  FormValue union extended to string[]; compactPayload skips []
- Fix stale test_smtp_relay_schema_matches_smtp: relay schema is a
  superset of smtp, not equal; update assertions accordingly

decnet/templates/http/Dockerfile

@@ -1,6 +1,10 @@
+FROM caddy:2 AS caddy-bin
+
 ARG BASE_IMAGE=debian:bookworm-slim@sha256:f9c6a2fd2ddbc23e336b6257a5245e31f996953ef06cd13a59fa0a1df2d5c252
 FROM ${BASE_IMAGE}
 
+COPY --from=caddy-bin /usr/bin/caddy /usr/bin/caddy
+
 RUN apt-get update && apt-get install -y --no-install-recommends \
     python3 python3-pip \
     && rm -rf /var/lib/apt/lists/*
@@ -14,12 +18,18 @@ COPY server.py /opt/server.py
 COPY entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
-EXPOSE 80 443
+EXPOSE 80
+
 RUN useradd -r -s /bin/false -d /opt logrelay \
+ && mkdir -p /etc/caddy /opt/.local/share/caddy /opt/.config/caddy \
+ && chown -R logrelay:logrelay /etc/caddy /opt/.local /opt/.config \
  && apt-get update && apt-get install -y --no-install-recommends libcap2-bin \
  && rm -rf /var/lib/apt/lists/* \
+ && setcap 'cap_net_bind_service+eip' /usr/bin/caddy \
  && (find /usr/bin/ -maxdepth 1 -name 'python3*' -type f -exec setcap 'cap_net_bind_service+eip' {} \; 2>/dev/null || true)
 
+ENV XDG_DATA_HOME=/opt/.local/share XDG_CONFIG_HOME=/opt/.config
+
 HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
   CMD kill -0 1 || exit 1
 

decnet/templates/http/entrypoint.sh

@@ -1,3 +1,43 @@
 #!/bin/bash
 set -e
-exec python3 /opt/server.py
+
+# Parse HTTP_VERSIONS JSON → Caddy protocol tokens (h1 / h2c)
+CADDY_PROTOCOLS=$(python3 -c "
+import json, os
+versions = json.loads(os.environ.get('HTTP_VERSIONS', '[\"http/1.1\"]'))
+tokens = []
+if 'http/1.1' in versions:
+    tokens.append('h1')
+if 'http/2' in versions:
+    tokens.append('h2c')
+print(' '.join(tokens) if tokens else 'h1')
+")
+
+cat > /etc/caddy/Caddyfile <<EOF
+{
+  admin off
+  servers :80 {
+    protocols ${CADDY_PROTOCOLS}
+  }
+}
+
+:80 {
+  reverse_proxy 127.0.0.1:8080
+}
+EOF
+
+python3 /opt/server.py &
+
+# Wait for Flask to be ready before handing off to Caddy
+python3 -c "
+import socket, time
+for _ in range(40):
+    try:
+        s = socket.create_connection(('127.0.0.1', 8080), timeout=0.25)
+        s.close()
+        break
+    except OSError:
+        time.sleep(0.1)
+"
+
+exec caddy run --config /etc/caddy/Caddyfile

decnet/templates/http/server.py

@@ -11,6 +11,7 @@ import os
 from pathlib import Path
 
 from flask import Flask, request, send_from_directory
+from werkzeug.middleware.proxy_fix import ProxyFix
 from werkzeug.serving import make_server, WSGIRequestHandler
 
 import instance_seed as _seed
@@ -27,7 +28,7 @@ logging.getLogger("werkzeug").setLevel(logging.ERROR)
 NODE_NAME     = os.environ.get("NODE_NAME", "webserver")
 SERVICE_NAME   = "http"
 LOG_TARGET    = os.environ.get("LOG_TARGET", "")
-PORT          = int(os.environ.get("PORT", "80"))
+PORT          = int(os.environ.get("PORT", "8080"))
 
 # Per-instance Server header. Every decky running one identical Apache
 # version string is a one-query fleet discovery for any scanner.
@@ -85,6 +86,7 @@ _FAKE_APP_BODIES: dict[str, str] = {
 }
 
 app = Flask(__name__)
+app.wsgi_app = ProxyFix(app.wsgi_app, x_for=1, x_proto=1, x_host=1)  # type: ignore[method-assign]
 
 @app.after_request
 def _fix_server_header(response):
@@ -161,5 +163,5 @@ class _SilentHandler(WSGIRequestHandler):
 
 if __name__ == "__main__":
     _log("startup", msg=f"HTTP server starting as {NODE_NAME}")
-    srv = make_server("0.0.0.0", PORT, app, request_handler=_SilentHandler)  # nosec B104
+    srv = make_server("127.0.0.1", PORT, app, request_handler=_SilentHandler)
     srv.serve_forever()