docs: document service-script env vars and split dev into daemon+app

Document the PASEO_SERVICE_<NAME>_URL/PORT and PASEO_URL/PORT contract exposed
by the service-script runtime. Split paseo.json's monolithic "server" script
into "daemon" and "app" services so peer discovery exercises the new env.

paseo.json

@@ -7,9 +7,13 @@
     ]
   },
   "scripts": {
-    "server": {
+    "daemon": {
       "type": "service",
-      "command": "npm run dev"
+      "command": "PASEO_LISTEN=0.0.0.0:$PASEO_PORT npm run dev:server"
+    },
+    "app": {
+      "type": "service",
+      "command": "cd packages/app && BROWSER=none EXPO_PUBLIC_LOCAL_DAEMON=\"${PASEO_SERVICE_DAEMON_URL#http://}\" npx expo start"
     },
     "typecheck": {
       "command": "npm run typecheck"