remove method_memoize to DRY caching

[RayBB]

Part of #11479

Some of this text was AI generated but I've closely guided and monitored the changes.

Remove method_memoize and Replace with Standard Python Caching

Summary

This PR removes the custom method_memoize decorator from the codebase and replaces it with standard Python caching patterns functools.cached_property.

Changes

Production Code

1. openlibrary/core/models.py:
   • Replace @cache.method_memoize with @functools.cached_property on:
     • Thing.get_history_preview()
     • Work.edition_count
   • Update callers to access get_history_preview as a property instead of a method call

Why It's Safe

What it does: functools.cached_property caches the result in the instance's __dict__ on first access. Subsequent accesses return the cached value without recomputing.

Why it's safe:

• Same behavior: Functionally equivalent to method_memoize for methods with no arguments
• Standard library: Part of Python 3.8+, well-tested and documented

Performance Considerations

As far as I know, there is no risk of performance changes.

Testing

Poking around the local website and looking at history and editions everything seems fine.

Stakeholders

@cdrini

[RayBB]

@cdrini I'm fairly confident in this PR but I'd love a second set of eyes on this by you!