Generate more typescript types and return conversation id with ConversationSummary (#3219)

This PR does multiple things that are necessary for conversation resume
to work from the extension. I wanted to make sure everything worked so
these changes wound up in one PR:
1. Generate more ts types
2. Resume rollout history files rather than create a new one every time
it is resumed so you don't see a duplicate conversation in history for
every resume. Chatted with @aibrahim-oai to verify this
3. Return conversation_id in conversation summaries
4. [Cleanup] Use serde and strong types for a lot of the rollout file
parsing

codex-rs/protocol/src/custom_prompts.rs

@@ -1,8 +1,9 @@
 use serde::Deserialize;
 use serde::Serialize;
 use std::path::PathBuf;
+use ts_rs::TS;
 
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, TS)]
 pub struct CustomPrompt {
     pub name: String,
     pub path: PathBuf,