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/agent/control_tests.rs

@@ -1211,6 +1211,7 @@ async fn spawn_agent_fork_from_paginated_parent_uses_model_context_prefix() {
                         permission_profile: PermissionProfile::workspace_write(),
                         active_permission_profile: None,
                         cwd: harness.config.cwd.clone(),
+                        runtime_workspace_roots: None,
                         reasoning_effort: None,
                         reasoning_summary: None,
                         personality: None,