chore(web): remove web_crawl tool + provider crawl plumbing (#33824)

The web_crawl_tool() function was an orphan — no model schema registered
it, no skill or CLI command called it, and the agent had no way to invoke
it. PR #32608 proposed wiring it up as a model-callable tool; we've
decided not to expose crawl as a separate capability since web_search +
web_extract cover the use cases we want models to have.

Removed:
- tools/web_tools.py: web_crawl_tool() (~230 LOC)
- plugins/web/firecrawl/provider.py: supports_crawl() + crawl()
- plugins/web/tavily/provider.py: supports_crawl() + crawl()
- plugins/web/xai/provider.py: supports_crawl() override
- agent/web_search_provider.py: supports_crawl() + crawl() ABC methods
- agent/web_search_registry.py: get_active_crawl_provider() +
  the 'crawl' branch in _resolve()
- agent/display.py: web_crawl tool-progress rendering
- hermes_cli/config.py: 'web_crawl' from TAVILY_API_KEY.tools
- tools/website_policy.py: stale comment reference
- Tests: removed TestWebCrawlTavily class, the two website-policy
  web_crawl tests, the searxng/ddgs/brave-free crawl-error tests,
  the integration test_web_crawl method, and the
  test_unconfigured_crawl_emits_top_level_error test. Trimmed the
  capability-flag parametrize list and the WebSearchProvider ABC
  conformance tests.
- Docs: trimmed the Crawl column from capability tables in both EN
  and zh-Hans, updated the developer-guide ABC table.

Net: 25 files, +115/-1067.

Closes #33762 (the schema-text bug only existed if #32608 landed).
Supersedes #32608.

website/i18n/zh-Hans/docusaurus-plugin-content-docs/current/developer-guide/web-search-provider-plugin.md

@@ -80,9 +80,6 @@ class MyBackendWebSearchProvider(WebSearchProvider):
     def supports_extract(self) -> bool:
         return False
 
-    def supports_crawl(self) -> bool:
-        return False
-
     def search(self, query: str, limit: int = 5) -> Dict[str, Any]:
         import httpx
 
@@ -157,12 +154,10 @@ requires_env:
 | `is_available()` | ✅ | — | 轻量可用性检查——环境变量、可选依赖等 |
 | `supports_search()` | — | `True` | `web_search` 路由的能力标志 |
 | `supports_extract()` | — | `False` | `web_extract` 路由的能力标志 |
-| `supports_crawl()` | — | `False` | 深度爬取模式的能力标志 |
 | `search(query, limit)` | 条件必须 | 抛出异常 | 当 `supports_search()` 返回 `True` 时必须实现 |
 | `extract(urls, **kwargs)` | 条件必须 | 抛出异常 | 当 `supports_extract()` 返回 `True` 时必须实现 |
-| `crawl(url, **kwargs)` | 条件必须 | 抛出异常 | 当 `supports_crawl()` 返回 `True` 时必须实现 |
 
-提供商可以在单个类中声明多种能力——Firecrawl、Tavily、Exa 和 Parallel 均实现了搜索/提取/爬取三种能力。Brave Search 和 DDGS 仅支持搜索；SearXNG 也仅支持搜索，并有文档说明的"与提取提供商配对使用"工作流。
+提供商可以在单个类中声明多种能力——Firecrawl、Tavily、Exa 和 Parallel 均实现了搜索和提取两种能力。Brave Search 和 DDGS 仅支持搜索；SearXNG 也仅支持搜索，并有文档说明的"与提取提供商配对使用"工作流。
 
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