feat: annotate conversations with model_provider for filtering (#5658)

Because conversations that use the Responses API can have encrypted
reasoning messages, trying to resume a conversation with a different
provider could lead to confusing "failed to decrypt" errors. (This is
reproducible by starting a conversation using ChatGPT login and resuming
it as a conversation that uses OpenAI models via Azure.)

This changes `ListConversationsParams` to take a `model_providers:
Option<Vec<String>>` and adds `model_provider` on each
`ConversationSummary` it returns so these cases can be disambiguated.

Note this ended up making changes to
`codex-rs/core/src/rollout/tests.rs` because it had a number of cases
where it expected `Some` for the value of `next_cursor`, but the list of
rollouts was complete, so according to this docstring:


bcd64c7e72/codex-rs/app-server-protocol/src/protocol.rs (L334-L337)

If there are no more items to return, then `next_cursor` should be
`None`. This PR updates that logic.






---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/openai/codex/pull/5658).
* #5803
* #5793
* __->__ #5658

codex-rs/tui/src/lib.rs

@@ -391,11 +391,14 @@ async fn run_ratatui_app(
             }
         }
     } else if cli.resume_last {
+        let provider_filter = vec![config.model_provider_id.clone()];
         match RolloutRecorder::list_conversations(
             &config.codex_home,
             1,
             None,
             INTERACTIVE_SESSION_SOURCES,
+            Some(provider_filter.as_slice()),
+            &config.model_provider_id,
         )
         .await
         {
@@ -407,7 +410,13 @@ async fn run_ratatui_app(
             Err(_) => resume_picker::ResumeSelection::StartFresh,
         }
     } else if cli.resume_picker {
-        match resume_picker::run_resume_picker(&mut tui, &config.codex_home).await? {
+        match resume_picker::run_resume_picker(
+            &mut tui,
+            &config.codex_home,
+            &config.model_provider_id,
+        )
+        .await?
+        {
             resume_picker::ResumeSelection::Exit => {
                 restore();
                 session_log::log_session_end();