[ty] Make lazy type traversal explicit

[charliermarsh]

Summary

All remaining callers of any_over_type and find_over_type use the old false behavior: walk stored nested types without evaluating lazy attributes. The flag no longer varies between callers, so we remove it and make that traversal the fixed behavior of both helpers.

Analyses that need lazy attributes now choose them explicitly. Visitors override the methods for the types they need to expand; for example, the recursion check explicitly visits alias values, protocol members, TypedDict fields, type-variable attributes, and NewType bases. Specialized alias searches can still compose the general helper: any_over_type_expanding_aliases uses it to walk stored types and explicitly recurses into alias values.

This preserves existing traversal behavior while removing the visitor-wide lazy-attribute switch and the shared search modes.

[astral-sh-bot]

Typing conformance results

No changes detected ✅

Current numbers

The percentage of diagnostics emitted that were expected errors held steady at 98.24%. The percentage of expected errors that received a diagnostic held steady at 98.24%. The number of fully passing files held steady at 134/146.

[astral-sh-bot]

Memory usage report

Memory usage unchanged ✅

[astral-sh-bot]

ecosystem-analyzer results

No diagnostic changes detected ✅

Full report with detailed diff (timing results)