Add Baidu Qianfan Coding Plan provider

[webup]

What

Adds Baidu Qianfan Coding Plan as an invited sponsor model provider in ClawMaster. The provider uses OpenClaw runtime id baiduqianfancodingplan, the documented BCE coding endpoint, OpenAI-compatible completions mode, and qianfan-code-latest as the default model.

Why

Baidu Qianfan Coding Plan is documented as an OpenClaw-compatible coding provider and should be discoverable from Setup and Models so users can configure it without editing openclaw.json manually.

How

• Added provider metadata, sponsor ordering, badge, fallback models, and zh/en/ja copy.
• Added frontend and backend live catalog allowlisting for the BCE coding endpoint and filtering for coding models.
• Updated setup, Models, adapter, catalog, desktop harness, UI plan, and contributing docs for the provider workflow.

Screenshots

Verified in Browser Use against http://127.0.0.1:16225/models: Qianfan appears as the default invited sponsor, saves the test key only in masked form, loads the live catalog, 测试连接 returns 连接正常, and the default model is baiduqianfancodingplan/qianfan-code-latest.

Related Issue

Closes #105

Type of Change

• Bug fix
• New feature
• Refactor (no behavior change)
• Documentation
• Tests
• CI / tooling
• Chore (dependencies, config)

Testing

• npm test passes locally
• npm run build --workspace=@openclaw-manager/web passes locally
• npm run build --workspace=@openclaw-manager/backend passes locally
• New or modified behavior has unit tests
• No console.log or debug artifacts left in code
• Browser Use UI walkthrough against the local web UI

Dependency Changes

• No new non-Node.js runtime dependencies introduced
• No new npm packages introduced

Checklist

• PR is a draft if not yet ready for review
• Branch name follows convention (feat/, fix/, chore/, docs/, test/, ci/)
• All new i18n strings added to packages/web/src/locales/main/{zh,en,ja}.ts