Add configurable memory versions with isolated storage (#43797)

## What changed

- Add `memories.version` with `v1` as the default and `v2` as an opt-in selection.
- Route memory generation, summaries, and retrieval tools through the selected version. Store `v2` artifacts in `memories_v2` and lazily create a separate SQLite database, keeping jobs and outputs isolated while sharing the thread catalog.
- Preserve the initial memory version across extension config updates so summaries and retrieval tools use the same namespace.
- Clear both versions on memory reset and remove thread memory from both stores on thread deletion. Recognize both artifact roots in shell usage telemetry.

## Testing

Add regression coverage for version defaults and validation, independent job claims and outputs, deletion and reset across versions, and shell usage classification for both memory roots.

GitOrigin-RevId: aa799bf87ab6ec10c8f5668213931e57547d080b

codex-rs/app-server/src/request_processors/thread_processor.rs

@@ -1866,13 +1866,9 @@ impl ThreadRequestProcessor {
             .clone()
             .ok_or_else(|| internal_error("sqlite state db unavailable for memory reset"))?;
 
-        state_db
-            .memories()
-            .clear_memory_data()
-            .await
-            .map_err(|err| {
-                internal_error(format!("failed to clear memory rows in memories db: {err}"))
-            })?;
+        state_db.clear_all_memory_data().await.map_err(|err| {
+            internal_error(format!("failed to clear memory rows in memories db: {err}"))
+        })?;
 
         clear_memory_roots_contents(&self.config.codex_home)
             .await