Improve node distance reranker speed

[prasmussen15]

:rocket:	This description was created by Ellipsis for commit 71920a98c773d0ede625ffe9d9ac58d322006d9c

perf: optimize node distance reranker and update podcast example

Summary:

Optimize node_distance_reranker(), update podcast_runner.py, and clean up test_graphiti_int.py.

Key points:

• Optimize node_distance_reranker() in search_utils.py using asyncio.gather for parallel execution.
• Update podcast_runner.py to process messages from 11 to 127 when use_bulk is False.
• Remove unused test code in test_graphiti_int.py related to build_communities() and initial search query.

---

Generated with :heart: by ellipsis.dev