AIStack v0.1.0

AIStack v0.1.0（GPL + 中英文双文档）

Highlights:

• License switched to GPL-3.0-or-later
• Chinese-first docs + English counterparts (*.en.md)
• MCP architecture docs and workflow diagrams
• VSCode extension packaged as aistack-0.1.0.vsix

Docs:

• README.md / README.en.md
• docs/ARCHITECTURE.md / docs/ARCHITECTURE.en.md
• docs/INSTALL.md / docs/INSTALL.en.md
• docs/SECURITY.md / docs/SECURITY.en.md
• docs/RELEASE.md / docs/RELEASE.en.md
• docs/VERSIONING.md / docs/VERSIONING.en.md
• docs/LICENSE_POLICY.md / docs/LICENSE_POLICY.en.md