chore: move mcp-server/src/wire_format.rs to protocol/src/mcp_protocol.rs (#2423)

The existing `wire_format.rs` should share more types with the
`codex-protocol` crate (like `AskForApproval` instead of maintaining a
parallel `CodexToolCallApprovalPolicy` enum), so this PR moves
`wire_format.rs` into `codex-protocol`, renaming it as
`mcp-protocol.rs`. We also de-dupe types, where appropriate.

---
[//]: # (BEGIN SAPLING FOOTER)
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* #2424
* __->__ #2423

codex-rs/core/src/config.rs

@@ -3,7 +3,6 @@ use crate::config_types::History;
 use crate::config_types::McpServerConfig;
 use crate::config_types::ReasoningEffort;
 use crate::config_types::ReasoningSummary;
-use crate::config_types::SandboxMode;
 use crate::config_types::SandboxWorkspaceWrite;
 use crate::config_types::ShellEnvironmentPolicy;
 use crate::config_types::ShellEnvironmentPolicyToml;
@@ -16,6 +15,7 @@ use crate::model_provider_info::built_in_model_providers;
 use crate::openai_model_info::get_model_info;
 use crate::protocol::AskForApproval;
 use crate::protocol::SandboxPolicy;
+use codex_protocol::config_types::SandboxMode;
 use dirs::home_dir;
 use serde::Deserialize;
 use std::collections::HashMap;

codex-rs/core/src/config_types.rs

@@ -78,21 +78,6 @@ pub enum HistoryPersistence {
 #[derive(Deserialize, Debug, Clone, PartialEq, Default)]
 pub struct Tui {}
 
-#[derive(Deserialize, Debug, Clone, Copy, PartialEq, Default, Serialize, Display)]
-#[serde(rename_all = "kebab-case")]
-#[strum(serialize_all = "kebab-case")]
-pub enum SandboxMode {
-    #[serde(rename = "read-only")]
-    #[default]
-    ReadOnly,
-
-    #[serde(rename = "workspace-write")]
-    WorkspaceWrite,
-
-    #[serde(rename = "danger-full-access")]
-    DangerFullAccess,
-}
-
 #[derive(Deserialize, Debug, Clone, PartialEq, Default)]
 pub struct SandboxWorkspaceWrite {
     #[serde(default)]

codex-rs/core/src/environment_context.rs

@@ -2,11 +2,11 @@ use serde::Deserialize;
 use serde::Serialize;
 use strum_macros::Display as DeriveDisplay;
 
-use crate::config_types::SandboxMode;
 use crate::models::ContentItem;
 use crate::models::ResponseItem;
 use crate::protocol::AskForApproval;
 use crate::protocol::SandboxPolicy;
+use codex_protocol::config_types::SandboxMode;
 use std::fmt::Display;
 use std::path::PathBuf;