Remove stray .snap.new filtering from schema fixtures reader

Motivation:
- `codex-app-server-protocol` schema fixtures are not insta snapshots.
- Filtering `*.snap.new` is confusing and risks hiding real files.

What changed:
- Remove the `.snap.new` filename special case in `read_schema_fixture_tree`.

Refs: macOS Bazel schema fixture mismatch investigation

codex-rs/app-server-protocol/schema/json/v1/AuthStatusChangeNotification.json

@@ -0,0 +1,46 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "AuthMode": {
+      "description": "Authentication mode for OpenAI-backed providers.",
+      "oneOf": [
+        {
+          "description": "OpenAI API key provided by the caller and stored by Codex.",
+          "enum": [
+            "apikey"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "ChatGPT OAuth managed by Codex (tokens persisted and refreshed by Codex).",
+          "enum": [
+            "chatgpt"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "[UNSTABLE] FOR OPENAI INTERNAL USE ONLY - DO NOT USE.\n\nChatGPT auth tokens are supplied by an external host app and are only stored in memory. Token refresh must be handled by the external host app.",
+          "enum": [
+            "chatgptAuthTokens"
+          ],
+          "type": "string"
+        }
+      ]
+    }
+  },
+  "description": "Deprecated notification. Use AccountUpdatedNotification instead.",
+  "properties": {
+    "authMethod": {
+      "anyOf": [
+        {
+          "$ref": "#/definitions/AuthMode"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    }
+  },
+  "title": "AuthStatusChangeNotification",
+  "type": "object"
+}