docs: add Continue and Cline config snippets

[haocn-ops]

Summary

• add a Continue.dev setup guide with the OpenAI-compatible Free-Way base URL
• add a Cline / Roo Code setup guide with the correct /v1 path shape
• link both guides from the README agent guide list

Closes #60.

Notes

This keeps the snippets provider-neutral and uses only the local Free-Way endpoint shape from the existing docs.

[GoDiao]

Thanks for adding these guides! The endpoint shape (http://localhost:8787/v1) looks right for OpenAI-compatible clients.

Before merging, could you update the Continue.dev guide to use the current config.yaml format? Continue’s docs now mark config.json as deprecated and show schema: v1 YAML examples for OpenAI-compatible providers:
https://docs.continue.dev/customize/model-providers/top-level/openai
https://docs.continue.dev/reference/yaml-migration

A minimal Free-Way example could be:

name: Free-Way
version: 1.0.0
schema: v1
models:
  - name: Free-Way
    provider: openai
    model: llama-3.3-70b
    apiBase: http://localhost:8787/v1
    apiKey: your FREEWAY_API_KEY

Also, since this PR adds links to README.md, could you add the matching links to README.zh-CN.md as well so the two READMEs stay in sync?