build: optimize dependencies management

[Ki-Seki]

Description

Summary: optimize dependencies management

Detailed description

⚙️ Dependency Management Overhaul

• Introduced @require_python_package decorator for dynamic imports of optional dependencies.
• Migrated from Poetry-only setup to PEP 621 standard with structured optional dependency groups.
• Removed deprecated configuration sections and refined version constraints.

🧪 CI/CD Pipeline Enhancements

• Added workflows for Python release testing and multi-platform wheel builds (including macOS 13).
• Implemented dependency validation to ensure no top-level optional imports.
• Improved test clarity with comments and slow-test reporting.

📦 Installation & Documentation Updates

• Updated installation instructions to reflect optional dependency usage.
• Refined Windows install commands using PowerShell syntax.
• Improved wheel and sdist installation steps for OS-specific handling.

🧹 Codebase Refactoring

• Converted imports in modules like Qdrant, sentence-transformers, scikit-learn, and schedule to dynamic.
• Added scripts/check_dependencies.py to validate dependency cleanliness.
• Updated test mocks and paths to align with new import structure.

Fix: #21 #40 #111 #115

Docs Issue/PR: MemTensor/MemOS-Docs#20

Reviewer: @CaralHsi @J1awei-Yang @fridayL @tangg555

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

[CaralHsi]

Nice work! Looks good to me.