Unified endpoint config type: one Host/IP : Port control in admin

New configSchema type 'endpoint' declared in the module spec: anything
that points at a device or service on the network must be one endpoint
field, rendered identically for every module in /admin as a joined
Host/IP : Port control and stored/handed to the module server as
{ host, port }. Migrates all three connection modules — ProdCom (was a
full URL field), ProPresenter and Timers (were separate host + port
fields). Legacy stored configs (prodcomUrl / flat host+port) keep
working until the admin form is re-saved, at which point the new shape
replaces them. MODULE-GUIDE documents the type and the presentation
rule: no split host/port fields, and full URLs only for genuine web
addresses.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RNYUv9EyrGSFmCnmH7WYKH

modules/propresenter-now-next/module.json

@@ -9,15 +9,10 @@
   "minSize": { "w": 3, "h": 3 },
   "defaultSize": { "w": 4, "h": 5 },
   "configSchema": {
-    "host": {
-      "type": "string",
-      "label": "ProPresenter host / IP",
-      "default": ""
-    },
-    "port": {
-      "type": "number",
-      "label": "ProPresenter network port",
-      "default": 1025
+    "propresenter": {
+      "type": "endpoint",
+      "label": "ProPresenter",
+      "default": { "host": "", "port": 1025 }
     },
     "password": {
       "type": "password",