collect_classes uses inconsistent key for retrieval tools

[MicaPerdomo]

Description

collect_classes stores retrieval tool entries using obj.__name__ (e.g., "ProductDocsSearch"), but collect_definitions resolves them using the explicit name attribute (e.g., "product_docs_search"). When the migration runner looks up classes by definition key, the mismatch causes a "retrieval is required for retrieval tool" error because the class cannot be found.

Steps to Reproduce

1. Define a BaseRetrievalTool with an explicit name attribute:

   class ProductDocsSearch(BaseRetrievalTool):
       name = "product_docs_search"
       retrieval = ProductDocsRetrieval

2. Run manage.py migrate agents.
3. The migration fails with: "retrieval is required for retrieval tool 'product_docs_search'".

Expected Behavior

collect_classes should use getattr(obj, "name", None) or obj.__name__ as the key, matching the logic in collect_definitions.

Actual Behavior

collect_classes uses obj.__name__ as the key. When collect_definitions looks up the class by the explicit name, it doesn't find it, and the retrieval reference cannot be resolved.