feat: add ArchiveConversation to ClientRequest (#3353)

Adds support for `ArchiveConversation` in the JSON-RPC server that takes
a `(ConversationId, PathBuf)` pair and:

- verifies the `ConversationId` corresponds to the rollout id at the
`PathBuf`
- if so, invokes
`ConversationManager.remove_conversation(ConversationId)`
- if the `CodexConversation` was in memory, send `Shutdown` and wait for
`ShutdownComplete` with a timeout
- moves the `.jsonl` file to `$CODEX_HOME/archived_sessions`

---------

Co-authored-by: Gabriel Peal <gabriel@openai.com>

codex-rs/protocol/src/mcp_protocol.rs

@@ -91,6 +91,11 @@ pub enum ClientRequest {
         request_id: RequestId,
         params: ResumeConversationParams,
     },
+    ArchiveConversation {
+        #[serde(rename = "id")]
+        request_id: RequestId,
+        params: ArchiveConversationParams,
+    },
     SendUserMessage {
         #[serde(rename = "id")]
         request_id: RequestId,
@@ -263,6 +268,18 @@ pub struct AddConversationSubscriptionResponse {
     pub subscription_id: Uuid,
 }
 
+/// The [`ConversationId`] must match the `rollout_path`.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct ArchiveConversationParams {
+    pub conversation_id: ConversationId,
+    pub rollout_path: PathBuf,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct ArchiveConversationResponse {}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]
 #[serde(rename_all = "camelCase")]
 pub struct RemoveConversationSubscriptionResponse {}