Update EverMemOS: optimize search perf, improve skill search

[shallyan]

Description

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test improvements
• Build/CI/CD changes

Related Issues

Fixes #
Relates to #

Changes Made

Testing

• Tested locally with manual verification
• Added/updated unit tests
• Added/updated integration tests
• All existing tests pass

Test Configuration:

• OS:
• Python version:
• Database versions (if relevant):

Test Results:

# Paste relevant test output here

Checklist

• My code follows the project's code style guidelines
• I have performed a self-review of my code
• I have commented my code where necessary, particularly in complex areas
• I have updated the documentation accordingly
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have used Gitmoji in my commit messages
• Any dependent changes have been merged and published

Screenshots (if applicable)

Additional Notes

Breaking Changes

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[cyfyifanchen]

LGTM