Conversation naming (#8991)

Session renaming:
- `/rename my_session`
- `/rename` without arg and passing an argument in `customViewPrompt`
- AppExitInfo shows resume hint using the session name if set instead of
uuid, defaults to uuid if not set
- Names are stored in `CODEX_HOME/sessions.jsonl`

Session resuming:
- codex resume <name> lookup for `CODEX_HOME/sessions.jsonl` first entry
matching the name and resumes the session

---------

Co-authored-by: jif-oai <jif@openai.com>

codex-rs/exec/src/cli.rs

@@ -114,7 +114,7 @@ pub enum Command {
 struct ResumeArgsRaw {
     // Note: This is the direct clap shape. We reinterpret the positional when --last is set
     // so "codex resume --last <prompt>" treats the positional as a prompt, not a session id.
-    /// Conversation/session id (UUID). When provided, resumes this session.
+    /// Conversation/session id (UUID) or thread name. UUIDs take precedence if it parses.
     /// If omitted, use --last to pick the most recent recorded session.
     #[arg(value_name = "SESSION_ID")]
     session_id: Option<String>,
@@ -144,7 +144,7 @@ struct ResumeArgsRaw {
 
 #[derive(Debug)]
 pub struct ResumeArgs {
-    /// Conversation/session id (UUID). When provided, resumes this session.
+    /// Conversation/session id (UUID) or thread name. UUIDs take precedence if it parses.
     /// If omitted, use --last to pick the most recent recorded session.
     pub session_id: Option<String>,