refactor: rename src/memory/expireEphemeral.js for clarity

[avoidwork]

Restructure Analysis: ./src/memory

Summary

The ./src/memory directory is relatively well-organized with 9 files at a single level. The primary finding is a minor naming inconsistency.

Findings

File/Directory	Issue Type	Impact	Summary	Recommendation
./src/memory/expireEphemeral.js	naming	low	Filename doesn't match the exported function name (expireEphemeralMemories)	Rename to expireEphemeralMemories.js for consistency

Proposed Structure

No structural changes needed. Just rename:

src/memory/expireEphemeral.js → src/memory/expireEphemeralMemories.js

Restructuring Priority

1. Rename expireEphemeral.js → expireEphemeralMemories.js
2. Update imports in context.js and index.js
3. Update exports in index.js