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/core/config.schema.json

@@ -2128,10 +2128,25 @@
         "use_memories": {
           "description": "When `false`, skip injecting memory usage instructions into developer prompts.",
           "type": "boolean"
+        },
+        "version": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/MemoryVersion"
+            }
+          ],
+          "description": "Selects the memory pipeline; v1 remains the default."
         }
       },
       "type": "object"
     },
+    "MemoryVersion": {
+      "enum": [
+        "v1",
+        "v2"
+      ],
+      "type": "string"
+    },
     "ModelAvailabilityNuxConfig": {
       "additionalProperties": {
         "format": "uint32",