Add NLI model for fast detection of duplication/conflict.

[bittergreen]

@CaralHsi

Description

feat: Add NLI model server/client code for fast detection of duplication/conflict.
test: Add test and example for NLI model.
feat: Init the NLI client when the server initializes.
fix: Avoid direct import of torch and transformers for the external NLI server.

Closes #950

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Unit Test - tests/memories/textual/test_pre_update_recaller.py and test_pre_update_recaller_latency.py

Checklist

• I have performed a self-review of my own code | 我已自行检查了自己的代码
• I have commented my code in hard-to-understand areas | 我已在难以理解的地方对代码进行了注释
• I have added tests that prove my fix is effective or that my feature works | 我已添加测试以证明我的修复有效或功能正常
• I have created related documentation issue/PR in MemOS-Docs (if applicable) | 我已在 MemOS-Docs 中创建了相关的文档 issue/PR（如果适用）
• I have linked the issue to this PR (if applicable) | 我已将 issue 链接到此 PR（如果适用）
• I have mentioned the person who will review this PR | 我已提及将审查此 PR 的人

Reviewer Checklist

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Made sure Checks passed
• Tests have been provided