Initial release: procd service and LuCI app for copyparty

OpenWrt procd service script and LuCI JavaScript interface for
copyparty (https://github.com/9001/copyparty), a self-hosted file
sharing server.

Features:
- procd service with UCI-driven volumes, accounts, and TLS cert
- LuCI view: settings, volume/account grids, live status + start/stop
- ACME TLS support via combined key+fullchain PEM (--cert flag)
- Auto-respawn and reload-on-config-change via service_triggers

etc/init.d/copyparty

@@ -0,0 +1,57 @@
+#!/bin/sh /etc/rc.common
+
+START=99
+USE_PROCD=1
+NAME=copyparty
+PROG=/usr/bin/python3
+
+_add_volume() {
+	local cfg="$1"
+	local src dst flags
+	config_get src   "$cfg" src
+	config_get dst   "$cfg" dst
+	config_get flags "$cfg" flags 'r'
+	[ -n "$src" ] && [ -n "$dst" ] && \
+		procd_append_param command -v "${src}:${dst}:${flags}"
+}
+
+_add_account() {
+	local cfg="$1"
+	local user pass
+	config_get user "$cfg" user
+	config_get pass "$cfg" pass
+	[ -n "$user" ] && [ -n "$pass" ] && \
+		procd_append_param command -a "${user}:${pass}"
+}
+
+start_service() {
+	config_load "$NAME"
+
+	local enabled
+	config_get_bool enabled config enabled 0
+	[ "$enabled" = "1" ] || return 0
+
+	local port name script usernames tls_cert
+	config_get port      config port      3923
+	config_get name      config name      'OWRT-NAS'
+	config_get script    config script    '/mnt/raid/copyparty-en.py'
+	config_get_bool usernames config usernames 0
+	config_get tls_cert  config tls_cert  ''
+
+	procd_open_instance
+	procd_set_param command "$PROG" "$script" -p "$port" --name "$name"
+	[ "$usernames" = "1" ] && procd_append_param command --usernames
+	[ -n "$tls_cert" ] && procd_append_param command --cert "$tls_cert"
+
+	config_foreach _add_volume  volume
+	config_foreach _add_account account
+
+	procd_set_param respawn
+	procd_set_param stdout 1
+	procd_set_param stderr 1
+	procd_close_instance
+}
+
+service_triggers() {
+	procd_add_reload_trigger "$NAME"
+}