Summary

This PR improves the repository's agent guidance documents and makes the guidance structure clearer and easier to maintain.

What changed

• refreshed the top-level AGENTS.md and AGENTS-CN.md
• kept the top-level English and Chinese guides aligned in structure and scope
• trimmed the documents to keep only stable, high-value guidance
• documented rule precedence for agent docs:
  • prefer the nearest AGENTS.md / AGENTS-CN.md
  • if local guidance conflicts with the repository-wide guide, follow the more specific, nearer document

Added module-level guides

Added focused guides for the main modules:

• src/web-ui/AGENTS.md
• src/web-ui/AGENTS-CN.md
• src/crates/core/AGENTS.md
• src/crates/core/AGENTS-CN.md
• src/apps/desktop/AGENTS.md
• src/apps/desktop/AGENTS-CN.md
• tests/e2e/AGENTS.md
• tests/e2e/AGENTS-CN.md
• BitFun-Installer/AGENTS.md
• BitFun-Installer/AGENTS-CN.md

Goals of the change

• make repository-wide guidance concise and stable
• move module-specific rules into module-local guides
• reduce duplication between top-level and module-level docs
• keep English and Chinese guidance consistent
• preserve existing narrow-scope rules such as:
  • src/crates/ai-adapters/AGENTS.md
  • src/crates/core/src/agentic/execution/AGENTS.md

Testing

• not run (documentation-only changes)