[app-server] feat: v2 Thread APIs (#6214)

Implements:
```
thread/list
thread/start
thread/resume
thread/archive
```

along with their integration tests. These are relatively light wrappers
around the existing core logic, and changes to core logic are minimal.

However, an improvement made for developer ergonomics:
- `thread/start` and `thread/resume` automatically attaches a
conversation listener internally, so clients don't have to make a
separate `AddConversationListener` call like they do today.

For consistency, also updated `model/list` and `feedback/upload` (naming
conventions, list API params).

codex-rs/Cargo.lock

@@ -186,9 +186,11 @@ dependencies = [
  "chrono",
  "codex-app-server-protocol",
  "codex-core",
+ "codex-protocol",
  "serde",
  "serde_json",
  "tokio",
+ "uuid",
  "wiremock",
 ]