feat(core): add exa url crawl tool (#12277)

Close [AI-126](https://linear.app/affine-design/issue/AI-126)

![截屏2025-05-14 17.01.19.png](https://graphite-user-uploaded-assets-prod.s3.amazonaws.com/sJGviKxfE3Ap685cl5bj/1a86ac68-f9f1-4740-8ddb-2293838682d2.png)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

- **New Features**
  - Introduced a new web crawling tool, allowing users to extract live content from specific web pages in addition to traditional web search.
- **Improvements**
  - Enhanced error handling for web search and web crawl operations, providing clearer failure messages.
  - Updated terminology in AI prompts and user-facing messages to reflect the new web search/crawl capabilities.
  - Improved formatting of web search and crawl results for better readability.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/plugins/copilot/tools/web-search.ts

@@ -14,21 +14,58 @@ export const createExaSearchTool = (config: Config) => {
         .describe('The mode to search the web for.'),
     }),
     execute: async ({ query, mode }) => {
-      const { key } = config.copilot.exa;
-      const exa = new Exa(key);
-      const result = await exa.searchAndContents(query, {
-        numResults: 10,
-        summary: true,
-        livecrawl: mode === 'MUST' ? 'always' : undefined,
-      });
-      return result.results.map(data => ({
-        title: data.title,
-        url: data.url,
-        summary: data.summary,
-        favicon: data.favicon,
-        publishedDate: data.publishedDate,
-        author: data.author,
-      }));
+      try {
+        const { key } = config.copilot.exa;
+        const exa = new Exa(key);
+        const result = await exa.searchAndContents(query, {
+          numResults: 10,
+          summary: true,
+          livecrawl: mode === 'MUST' ? 'always' : undefined,
+        });
+        return result.results.map(data => ({
+          title: data.title,
+          url: data.url,
+          content: data.summary,
+          favicon: data.favicon,
+          publishedDate: data.publishedDate,
+          author: data.author,
+        }));
+      } catch {
+        return 'Failed to search the web';
+      }
+    },
+  });
+};
+
+export const createExaCrawlTool = (config: Config) => {
+  return tool({
+    description: 'Crawl the web url for information',
+    parameters: z.object({
+      url: z
+        .string()
+        .describe('The URL to crawl (including http:// or https://)'),
+    }),
+    execute: async ({ url }) => {
+      try {
+        const { key } = config.copilot.exa;
+        const exa = new Exa(key);
+        const result = await exa.getContents([url], {
+          livecrawl: 'always',
+          text: {
+            maxCharacters: 100000,
+          },
+        });
+        return result.results.map(data => ({
+          title: data.title,
+          url: data.url,
+          content: data.text,
+          favicon: data.favicon,
+          publishedDate: data.publishedDate,
+          author: data.author,
+        }));
+      } catch {
+        return 'Failed to crawl the web url';
+      }
     },
   });
 };