chore(config) Rename config setting to personality (#10314)

## Summary
Let's make the setting name consistent with the SlashCommand!

## Testing
- [x] Updated tests

codex-rs/core/config.schema.json

@@ -261,9 +261,6 @@
           ],
           "description": "Optional path to a file containing model instructions."
         },
-        "model_personality": {
-          "$ref": "#/definitions/Personality"
-        },
         "model_provider": {
           "description": "The key in the `model_providers` map identifying the [`ModelProviderInfo`] to use.",
           "type": "string"
@@ -280,6 +277,9 @@
         "oss_provider": {
           "type": "string"
         },
+        "personality": {
+          "$ref": "#/definitions/Personality"
+        },
         "sandbox_mode": {
           "$ref": "#/definitions/SandboxMode"
         },
@@ -1376,14 +1376,6 @@
       ],
       "description": "Optional path to a file containing model instructions that will override the built-in instructions for the selected model. Users are STRONGLY DISCOURAGED from using this field, as deviating from the instructions sanctioned by Codex will likely degrade model performance."
     },
-    "model_personality": {
-      "allOf": [
-        {
-          "$ref": "#/definitions/Personality"
-        }
-      ],
-      "description": "EXPERIMENTAL Optionally specify a personality for the model"
-    },
     "model_provider": {
       "description": "Provider to use from the model_providers map.",
       "type": "string"
@@ -1442,6 +1434,14 @@
       ],
       "description": "OTEL configuration."
     },
+    "personality": {
+      "allOf": [
+        {
+          "$ref": "#/definitions/Personality"
+        }
+      ],
+      "description": "Optionally specify a personality for the model"
+    },
     "profile": {
       "description": "Profile to use from the `profiles` map.",
       "type": "string"
@@ -1569,4 +1569,4 @@
   },
   "title": "ConfigToml",
   "type": "object"
-}
+}