add none personality option (#10688)

- add none personality enum value and empty placeholder behavior\n- add
docs/schema updates and e2e coverage

codex-rs/docs/codex_mcp_interface.md

@@ -73,6 +73,8 @@ Send input to the active turn:
 - `sendUserMessage` → enqueue items to the conversation
 - `sendUserTurn` → structured turn with explicit `cwd`, `approvalPolicy`, `sandboxPolicy`, `model`, optional `effort`, `summary`, optional `personality`, and optional `outputSchema` (JSON Schema for the final assistant message)
 
+Valid `personality` values are `friendly`, `pragmatic`, and `none`. When `none` is selected, the personality placeholder is replaced with an empty string.
+
 For v2 threads, `turn/start` also accepts `outputSchema` to constrain the final assistant message for that turn.
 
 Interrupt a running turn: `interruptConversation`.

codex-rs/docs/protocol_v1.md

@@ -72,6 +72,9 @@ For complete documentation of the `Op` and `EventMsg` variants, refer to [protoc
   - `Op::UserInputAnswer` – Provide answers for a `request_user_input` tool call
   - `Op::ListSkills` – Request skills for one or more cwd values (optionally `force_reload`)
   - `Op::UserTurn` and `Op::OverrideTurnContext` accept an optional `personality` override that updates the model’s communication style
+
+Valid `personality` values are `friendly`, `pragmatic`, and `none`. When `none` is selected, the personality placeholder is replaced with an empty string.
+
 - `EventMsg`
   - `EventMsg::AgentMessage` – Messages from the `Model`
   - `EventMsg::AgentMessageContentDelta` – Streaming assistant text