### Change summary
Defer rollout file creation until needed.
* Add a core API to force rollout persistence for loaded non-ephemeral threads:
* seeds initial context if needed
* flushes rollout and returns persisted path
Add concurrency guard to make lazy rollout initialization idempotent under concurrent calls.
Add centralized app-server rollout-path resolver that:
* uses in-memory thread state when loaded
* forces persistence on demand for rollout-dependent calls
* falls back to on-disk lookup for unloaded threads
* maps ephemeral threads to invalid-request errors for rollout-dependent operations
Route rollout-dependent endpoints through the resolver (v2 + shared legacy surfaces), including:
* thread/archive
* thread/resume (thread-id path)
* thread/fork (thread-id path)
* resumeConversation
* forkConversation
* thread summary by thread id
* detached review parent-thread path resolution
* feedback include_logs rollout resolution
Remove stale cached rollout-path assumptions in rollback/detached-review flows by resolving via thread id when needed.
No wire-schema changes; behavior-only change.
v1 compatibility is not expanded in this PR.
### Tests updated/added
* thread_start: assert rollout is absent immediately after thread/start; created after first completed turn.
* thread_resume: resume by thread id succeeds for just-started thread via on-demand persistence; path-vs-thread-id precedence test updated.
* thread_fork: fork by thread id succeeds for just-started thread.
* thread_archive: archive succeeds for just-started thread and materializes before archive.
* thread_unarchive: adjusted for deferred creation timing.
* thread_rollback: rollback path no longer depends on stale cached rollout path.
* Detached review targeted test verified for lazy path behavior.
* Core tests for new persistence API
This adds the following fields to `ThreadStartResponse` and
`ThreadResumeResponse`:
```rust
pub model: String,
pub model_provider: String,
pub cwd: PathBuf,
pub approval_policy: AskForApproval,
pub sandbox: SandboxPolicy,
pub reasoning_effort: Option<ReasoningEffort>,
```
This is important because these fields are optional in
`ThreadStartParams` and `ThreadResumeParams`, so the caller needs to be
able to determine what values were ultimately used to start/resume the
conversation. (Though note that any of these could be changed later
between turns in the conversation.)
Though to get this information reliably, it must be read from the
internal `SessionConfiguredEvent` that is created in response to the
start of a conversation. Because `SessionConfiguredEvent` (as defined in
`codex-rs/protocol/src/protocol.rs`) did not have all of these fields, a
number of them had to be added as part of this PR.
Because `SessionConfiguredEvent` is referenced in many tests, test
instances of `SessionConfiguredEvent` had to be updated, as well, which
is why this PR touches so many files.
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).
