Gate realtime audio interruption logic to v2 (#14984)

- thread the realtime version into conversation start and app-server
notifications
- keep playback-aware mic gating and playback interruption behavior on
v2 only, leaving v1 on the legacy path

codex-rs/core/config.schema.json

@@ -1359,6 +1359,13 @@
       },
       "type": "object"
     },
+    "RealtimeConversationVersion": {
+      "enum": [
+        "v1",
+        "v2"
+      ],
+      "type": "string"
+    },
     "RealtimeToml": {
       "additionalProperties": false,
       "properties": {
@@ -1366,7 +1373,7 @@
           "$ref": "#/definitions/RealtimeWsMode"
         },
         "version": {
-          "$ref": "#/definitions/RealtimeWsVersion"
+          "$ref": "#/definitions/RealtimeConversationVersion"
         }
       },
       "type": "object"
@@ -1378,13 +1385,6 @@
       ],
       "type": "string"
     },
-    "RealtimeWsVersion": {
-      "enum": [
-        "v1",
-        "v2"
-      ],
-      "type": "string"
-    },
     "ReasoningEffort": {
       "description": "See https://platform.openai.com/docs/guides/reasoning?api-mode=responses#get-started-with-reasoning",
       "enum": [