docs(i18n): update zh-CN README to match ja/en structure (#268)

* docs(i18n): update zh-CN README to match ja/en structure
- Rewrite zh-CN README based on ja version for consistency
- Add Identity Management UI section
- Add Delete Identity command to commands table
- Add SSH key management details section
- Add IdentitiesOnly yes explanation section
- Update image paths to zh-CN localized versions
- Update Quick Start to new UI-based setup flow

🖥️ IDE: [Cursor](https://cursor.sh)
🔌 Extension: [Claude Code](https://claude.ai/download)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Model-Raw: claude-opus-4-5-20251101

* chore: add lint-staged for automatic markdown formatting
- Install lint-staged as dev dependency
- Configure lint-staged to run prettier on *.md files
- Add lint-staged to husky pre-commit hook
- Apply prettier formatting to zh-CN README

🖥️ IDE: [Cursor](https://cursor.sh)
🔌 Extension: [Claude Code](https://claude.ai/download)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Model-Raw: claude-opus-4-5-20251101

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: nullvariant

.husky/pre-commit

@@ -1,4 +1,7 @@
 #!/usr/bin/env sh
+# Run lint-staged for prettier formatting on staged files
+npx lint-staged
+
 # Auto-regenerate README.md when i18n/en/README.md changes
 # This ensures all commits are signed by the developer, not by GitHub Actions