thread-store: store permission profiles (#23165)

## Why

`SandboxPolicy` is the legacy compatibility shape, but
`codex-thread-store` still exposed it through `StoredThread`,
`ThreadMetadataPatch`, and live metadata sync. That kept thread-store
consumers tied to the legacy representation and meant richer permission
profile data could not round-trip through thread metadata or cold
rollout reconciliation.

## What Changed

- Replaced thread-store `sandbox_policy` API fields with canonical
`PermissionProfile` fields.
- Persist new permission-profile metadata as canonical JSON in the
existing SQLite metadata slot while continuing to read older legacy
sandbox policy values.
- Updated local, in-memory, live metadata sync, and rollout extraction
paths to propagate `TurnContextItem::permission_profile()`.
- Re-materialize legacy permission metadata against the final rollout
cwd when rollout-derived metadata replaces stale SQLite summaries.
- Updated affected app-server and core test constructors to build
`PermissionProfile` values directly.

## Test Plan

- `cargo test -p codex-state`
- `cargo test -p codex-thread-store`
- `cargo test -p codex-app-server
summary_from_stored_thread_preserves_millisecond_precision --lib`
- `cargo test -p codex-core realtime_context --lib`

codex-rs/thread-store/src/thread_metadata_sync.rs

@@ -234,7 +234,7 @@ impl ThreadMetadataSync {
                     update.model = Some(turn_ctx.model.clone());
                     update.reasoning_effort = turn_ctx.effort;
                     update.approval_mode = Some(turn_ctx.approval_policy);
-                    update.sandbox_policy = Some(turn_ctx.sandbox_policy.clone());
+                    update.permission_profile = Some(turn_ctx.permission_profile());
                 }
                 RolloutItem::EventMsg(EventMsg::UserMessage(user)) => {
                     if let Some(preview) = user_message_preview(user) {
@@ -354,7 +354,7 @@ fn update_has_metadata_facts(update: &ThreadMetadataPatch) -> bool {
         || update.cwd.is_some()
         || update.cli_version.is_some()
         || update.approval_mode.is_some()
-        || update.sandbox_policy.is_some()
+        || update.permission_profile.is_some()
         || update.token_usage.is_some()
         || update.first_user_message.is_some()
         || update.git_info.is_some()