feat: add Brave Search & Baidu Search integration with sub-source support

[YizukiAme]

Summary

Adds Brave Search and Baidu Search as web search providers, with Baidu sub-source configuration (Web Search, Baike, Scholar).

Changes

New Search Providers

• Brave Search: Uses public page scraping — no API key required. Parses Brave's Svelte-rendered HTML to extract search results.
• Baidu Search: Integrates Web Search, Baike (encyclopedia), and Scholar APIs. Users can toggle individual sub-sources on/off.

Provider Icons

• Added icons for Brave (public/icons/brave.png), Baidu (public/icons/baidu.png), and Tavily (public/icons/tavily.jpg)
• Icons displayed in toolbar pill, provider dropdown, and settings sidebar

UI Improvements

• Baidu sub-source toggles use standard Switch components (consistent with rest of the UI)
• Brave API key field shown but marked optional with explanatory notice
• Search toggle enabled when any provider is available (not just selected one)

Technical Details

• lib/web-search/brave.ts: Regex-based HTML parser for Brave's current Svelte-rendered page structure
• lib/web-search/baidu.ts: Accepts subSources parameter, queries enabled sources in parallel
• lib/store/settings.ts: Added baiduSubSources state with per-source toggles
• app/api/web-search/route.ts: Brave bypasses API key check; Baidu passes sub-source config
• components/generation/generation-toolbar.tsx: Fixed webSearchAvailable logic

Files Changed

File	Description
lib/web-search/brave.ts	Fixed HTML parser for current Brave Search structure
lib/web-search/baidu.ts	Added sub-source toggle support
lib/web-search/types.ts	Added BaiduSubSources interface
lib/web-search/constants.ts	Added sub-source config, icon paths
lib/store/settings.ts	Added Baidu sub-source state
app/api/web-search/route.ts	Brave no-key logic, Baidu sub-sources
app/generation-preview/page.tsx	Pass sub-sources in API call
components/settings/web-search-settings.tsx	Sub-source toggles, optional key UI
components/generation/generation-toolbar.tsx	Icons, fixed availability logic
public/icons/*	Provider icons

Testing

• ✅ Baidu Search returns results (verified via API call with key)
• ✅ Brave Search parser matches current HTML structure (tested with saved HTML, 20 results parsed)
• ✅ Build passes (pnpm build exit code 0)
• ✅ UI verified: icons display correctly, search toggle enables properly, Baidu sub-source switches render consistently

[wyuc]

Thanks for the contribution, and sorry for the long delay on my side.

This PR is now quite far behind main and conflicts with the current web-search architecture, so it is not mergeable as-is. There are also a few areas that would need another look after an update, including how the new providers plug into the current searchWeb flow, server-side classroom generation, Baidu sub-source handling, and test coverage for the Brave parser.

If you’re still interested in maintaining this PR, please rebase it onto the latest main and adapt it to the current web-search provider architecture. I’ll be happy to review it again after that.

[YizukiAme]

Got it! I'll rebase this onto main and update the code to fit the current architecture in a couple of days when I have some bandwidth.
Thanks for the review~

[YizukiAme]

Done~

[wyuc]

Reviewed PR #42 and tested the new web search providers locally.

Overall this looks good for Brave and for Baidu Web/Baike. Brave official API mode worked in a real generation flow with Gemini 3 Flash, and Baidu Web/Baike also return usable results with the configured key.

A few issues I’d fix before merge:

1. Baidu Scholar response parsing does not match the official schema.
   In lib/web-search/baidu.ts, the code currently checks data.code !== 0 and reads data.results, but the official Baidu Scholar response uses string code "0" and returns papers under data.
   This means Scholar results will parse as empty or be treated as failed even after the key is properly authorized.

2. Scholar abstract parameter should use enable_ai_abstract.
   The docs’ parameter table names this field enable_ai_abstract; the docs example is inconsistent, but using the parameter-table name is safer.

3. .env.example is missing BRAVE_API_KEY.
   The implementation supports Brave official API mode via server config, but the example env only documents Baidu/Tavily/Bocha. Please add BRAVE_API_KEY= so deployers can discover the intended env var.

4. Tests should clear Brave env vars.
   tests/server/web-search-config.test.ts and tests/web-search/route.test.ts reset Tavily/Bocha/Baidu env vars but not BRAVE_API_KEY / BRAVE_BASE_URL, so local or CI env can leak into tests.

One note on Scholar availability: the URL itself appears correct. Opening it without auth returns Baidu’s get authorization error, so the route is real. With the current key, Scholar returned 404, which looks like a Baidu-side authorization/enablement issue for that tool rather than a URL issue. The UI should probably indicate that Baidu Scholar may require separate authorization, or at least fail visibly enough that users don’t assume the toggle is working when it returns no sources.

Tested:

• pnpm exec tsc --noEmit --pretty false
• targeted web-search/provider tests
• pnpm lint
• pnpm build
• pnpm test:e2e
• real Brave + Gemini 3 Flash first-page generation with screenshots

[YizukiAme]

Thanks so much for the thorough review!! All points are confirmed — working on it 👍

[YizukiAme]

All 4 items addressed in 5b61acf ~ 😊

1. Baidu Scholar response parsing

• code type: number → string (matches "0")
• Results array: results → data
• BaiduScholarPaper interface aligned to official schema (aiAbstract, doi, paperId, publishInfo, publishYear as number)
• aiAbstract now included in content pipeline

2. Scholar parameter name

• enable_abstract → enable_ai_abstract (following the parameter table, not the inconsistent curl example)

3. .env.example missing BRAVE_API_KEY

• Added BRAVE_API_KEY=

4. Tests should clear Brave env vars

• Added delete process.env.BRAVE_API_KEY / BRAVE_BASE_URL in both web-search-config.test.ts and route.test.ts beforeEach

Bonus: Scholar authorization UX

• Added "API Docs ↗" links to all three Baidu sub-sources (Web Search, Baike, Scholar) in the settings UI, pointing to official Baidu documentation. This helps users discover free tier limits (Scholar: 50 calls/day) and authorization requirements. Fully i18n'd across all 6 locales.

[wyuc]

LGTM. Re-ran focused tests and E2E, including real Brave Search + Gemini first-page generation on 5d88c72.