♻️ Unify prompt filename

[SimengBian]

1. Unify prompt filename: all English versions end with _en and all Chinese versions end with _zh
2. Revise prompt of knowledge base summary to avoid "this cluster/本簇" expressions [Improvement] The concept of clusters should not be reflected in the knowledge base summary #1680

TODO: Useless prompts and codes in knowledge base summary function will be cleared in the next step

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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