fix: add durable Hermes provider link

[RerankerGuo]

Description

Fixes #1744.

Hermes provider installation now writes two provider links: the checkout-local plugins/memory/memtensor path used by the current runtime, plus a user-level ~/.hermes/plugins/memory/memtensor link that survives Hermes checkout replacement during upgrades. The adapter-specific installer and Windows installer use the same durable location, and the provider manifest copy remains unchanged.

A small install regression test checks the Unix, adapter, and PowerShell installers so future changes keep both provider paths wired.

Related Issue (Required): Fixes #1744

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• Documentation update

How Has This Been Tested?

• Unit Test
• Test Script Or Test Steps (please provide)
• Pipeline Automated API Test (please provide)

Commands run:

cd apps/memos-local-plugin && npm test -- --run tests/unit/install/hermes-provider-link.test.ts
cd apps/memos-local-plugin && npm run lint
make format

Results:

• npm test -- --run tests/unit/install/hermes-provider-link.test.ts: 1 file passed, 3 tests passed.
• npm run lint: tsc -p tsconfig.json --noEmit completed successfully.
• make format: blocked locally because poetry is not installed (make: poetry: Command not found).

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 fix: Hermes provider symlink breaks after upgrade and bridge health can timeout during startup recovery #1744
• Made sure Checks passed
• Tests have been provided