feat: gen memories config (#12999)

codex-rs/core/config.schema.json

@@ -613,6 +613,10 @@
       "additionalProperties": false,
       "description": "Memories settings loaded from config.toml.",
       "properties": {
+        "generate_memories": {
+          "description": "When `false`, newly created threads are stored with `memory_mode = \"disabled\"` in the state DB.",
+          "type": "boolean"
+        },
         "max_raw_memories_for_global": {
           "description": "Maximum number of recent raw memories retained for global consolidation.",
           "format": "uint",