Preserve runtime workspace roots across thread resume (#43848)

## Why

Resuming a thread should retain its selected workspace folders, including additional roots and explicit empty selections. Resume overrides also need to survive a subsequent resume when no turn has run.

## What changed

- Persist `runtime_workspace_roots` in startup metadata and thread settings snapshots, separately from explicit environment selections and permission-profile roots.
- Restore roots from the latest snapshot owned by the resumed thread, falling back to owned startup metadata only when no snapshot exists. Honor explicit `runtimeWorkspaceRoots` overrides, retarget the old `cwd` root when `cwd` changes, deduplicate roots, and validate restored paths for the current host.
- Checkpoint effective settings on resume and restored settings after revert. Reload resume configuration if saved workspace roots change during loading.
- Normalize Windows rollout path spellings when matching thread search results, preserving selection of the correct rollout after revert, including compressed rollouts.

## Testing

Add regression coverage for workspace restoration, empty and explicit overrides, foreign paths, compaction and revert, resume checkpoints without recency changes, concurrent settings persistence, and rollout search path matching.

GitOrigin-RevId: d98d9d34dd63934d441120916c61c12b69e7f062

codex-rs/core/src/codex_thread.rs

@@ -138,6 +138,7 @@ impl ThreadConfigSnapshot {
 #[derive(Clone, Default)]
 pub struct CodexThreadSettingsOverrides {
     pub environments: Option<TurnEnvironmentSelections>,
+    pub runtime_workspace_roots: Option<Vec<AbsolutePathBuf>>,
     pub profile_workspace_roots: Option<Vec<AbsolutePathBuf>>,
     pub approval_policy: Option<AskForApproval>,
     pub approvals_reviewer: Option<ApprovalsReviewer>,
@@ -535,9 +536,17 @@ impl CodexThread {
         self.session.update_settings(updates).await.map(|_| ())
     }
 
+    /// Persists current settings without emitting a live settings event.
+    ///
+    /// Serializes snapshot capture and persistence with accepted settings updates.
+    pub async fn checkpoint_thread_settings(&self) -> ThreadStoreResult<()> {
+        self.session.checkpoint_thread_settings().await
+    }
+
     fn thread_settings_update(overrides: CodexThreadSettingsOverrides) -> SessionSettingsUpdate {
         let CodexThreadSettingsOverrides {
             environments,
+            runtime_workspace_roots,
             profile_workspace_roots,
             approval_policy,
             approvals_reviewer,
@@ -564,6 +573,7 @@ impl CodexThread {
                 approvals_reviewer,
             },
             environments,
+            runtime_workspace_roots,
             profile_workspace_roots,
             sandbox_policy,
             permission_profile,