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.

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

codex-rs/exec/Cargo.toml

@@ -26,6 +26,7 @@ codex-common = { path = "../common", features = [
 ] }
 codex-core = { path = "../core" }
 codex-ollama = { path = "../ollama" }
+codex-protocol = { path = "../protocol" }
 owo-colors = "4.2.0"
 serde_json = "1"
 shlex = "1.3.0"
@@ -41,8 +42,8 @@ tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }
 
 [dev-dependencies]
 assert_cmd = "2"
+core_test_support = { path = "../core/tests/common" }
 libc = "0.2"
 predicates = "3"
 tempfile = "3.13.0"
 wiremock = "0.6"
-core_test_support = { path = "../core/tests/common" }

codex-rs/exec/src/lib.rs

@@ -13,7 +13,6 @@ use codex_core::ConversationManager;
 use codex_core::NewConversation;
 use codex_core::config::Config;
 use codex_core::config::ConfigOverrides;
-use codex_core::config_types::SandboxMode;
 use codex_core::protocol::AskForApproval;
 use codex_core::protocol::Event;
 use codex_core::protocol::EventMsg;
@@ -22,6 +21,7 @@ use codex_core::protocol::Op;
 use codex_core::protocol::TaskCompleteEvent;
 use codex_core::util::is_inside_git_repo;
 use codex_ollama::DEFAULT_OSS_MODEL;
+use codex_protocol::config_types::SandboxMode;
 use event_processor_with_human_output::EventProcessorWithHumanOutput;
 use event_processor_with_json_output::EventProcessorWithJsonOutput;
 use tracing::debug;