fix: address remaining Cubic review comments (P2 issues)

- Add content-based fallback matching for todos without ids

- Add TODO comment for exported but unused SDK functions

- Add resetStorageClient() for test isolation

- Fixes todo duplication risk on beta (SQLite backend)

src/features/hook-message-injector/injector.ts

@@ -49,6 +49,11 @@ function convertSDKMessageToStoredMessage(msg: SDKMessage): StoredMessage | null
   }
 }
 
+// TODO: These SDK-based functions are exported for future use when hooks migrate to async.
+// Currently, callers still use the sync JSON-based functions which return null on beta.
+// Migration requires making callers async, which is a larger refactoring.
+// See: https://github.com/code-yeongyu/oh-my-opencode/pull/1837
+
 /**
  * Finds the nearest message with required fields using SDK (for beta/SQLite backend).
  * Uses client.session.messages() to fetch message data from SQLite.