[codex] Add local thread store listing (#17824)

Builds on top of #17659 

Move the filesystem + sqlite thread listing-related operations inside of
a local ThreadStore implementation and call ThreadStore from the places
that used to perform these filesystem/sqlite operations.

This is the first of a series of PRs that will implement the rest of the
local ThreadStore.

Testing:
- added unit tests for the thread store implementation
- adjusted some unit tests in the realtime + personality packages whose
callsites changed. Specifically I'm trying to hide ThreadMetadata inside
of the local implementation and make ThreadMetadata a sqlite
implementation detail concern rather than a public interface, preferring
the more generate StoredThread interface instead
- added a corner case test for the personality migration package that
wasn't covered by the existing test suite
- adjust the behavior of searched thread listing to run the existing
local rollout repair/backfill pass _before_ querying SQLite results, so
callers using ThreadStore::list_threads do not miss matches after a
partial metadata warm-up

codex-rs/Cargo.lock

@@ -1461,6 +1461,7 @@ dependencies = [
  "codex-sandboxing",
  "codex-shell-command",
  "codex-state",
+ "codex-thread-store",
  "codex-tools",
  "codex-utils-absolute-path",
  "codex-utils-cargo-bin",
@@ -1938,6 +1939,7 @@ dependencies = [
  "codex-state",
  "codex-terminal-detection",
  "codex-test-binary-support",
+ "codex-thread-store",
  "codex-tools",
  "codex-utils-absolute-path",
  "codex-utils-cache",
@@ -2841,9 +2843,17 @@ version = "0.0.0"
 dependencies = [
  "async-trait",
  "chrono",
+ "codex-git-utils",
  "codex-protocol",
+ "codex-rollout",
+ "codex-state",
+ "pretty_assertions",
  "serde",
+ "serde_json",
+ "tempfile",
  "thiserror 2.0.18",
+ "tokio",
+ "uuid",
 ]
 
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