feat(mcp): persist and display marketplace README

Capture the README markdown from LangBot Space when installing an MCP
server and store it on the mcp_servers record (new readme column +
alembic migration 0004). The detail page can then render docs offline,
independent of the server's runtime/connection state.

web/src/app/home/mcp/components/mcp-form/MCPReadme.tsx

@@ -0,0 +1,74 @@
+import ReactMarkdown from 'react-markdown';
+import remarkGfm from 'remark-gfm';
+import rehypeRaw from 'rehype-raw';
+import rehypeSanitize from 'rehype-sanitize';
+import rehypeHighlight from 'rehype-highlight';
+import rehypeSlug from 'rehype-slug';
+import rehypeAutolinkHeadings from 'rehype-autolink-headings';
+import { useTranslation } from 'react-i18next';
+import '@/styles/github-markdown.css';
+
+/**
+ * Renders the README markdown captured from LangBot Space at install time.
+ * The README is stored on the MCP server record (``server.readme``) so this
+ * works offline and regardless of the server's runtime/connection state.
+ *
+ * MCP marketplace READMEs reference images by absolute URL (the upstream repo),
+ * so — unlike plugin READMEs — no asset-path rewriting is needed here.
+ */
+export default function MCPReadme({ readme }: { readme?: string }) {
+  const { t } = useTranslation();
+
+  if (!readme || !readme.trim()) {
+    return (
+      <div className="flex min-h-[220px] items-center justify-center rounded-lg border border-dashed text-sm text-muted-foreground">
+        {t('mcp.noReadme')}
+      </div>
+    );
+  }
+
+  return (
+    <div className="w-full overflow-auto">
+      <div className="markdown-body max-w-none p-1 pt-0">
+        <ReactMarkdown
+          remarkPlugins={[remarkGfm]}
+          rehypePlugins={[
+            rehypeRaw,
+            rehypeSanitize,
+            rehypeHighlight,
+            rehypeSlug,
+            [
+              rehypeAutolinkHeadings,
+              {
+                behavior: 'wrap',
+                properties: {
+                  className: ['anchor'],
+                },
+              },
+            ],
+          ]}
+          components={{
+            ul: ({ children }) => <ul className="list-disc">{children}</ul>,
+            ol: ({ children }) => <ol className="list-decimal">{children}</ol>,
+            li: ({ children }) => <li className="ml-4">{children}</li>,
+            a: ({ children, href, ...props }) => (
+              <a href={href} target="_blank" rel="noopener noreferrer" {...props}>
+                {children}
+              </a>
+            ),
+            img: ({ src, alt, ...props }) => (
+              <img
+                src={src}
+                alt={alt || ''}
+                className="my-4 h-auto max-w-full rounded-lg"
+                {...props}
+              />
+            ),
+          }}
+        >
+          {readme}
+        </ReactMarkdown>
+      </div>
+    </div>
+  );
+}

web/src/app/infra/entities/api/index.ts

@@ -551,6 +551,7 @@ export type MCPServer =
       enable: boolean;
       extra_args: MCPServerExtraArgsSSE;
       runtime_info?: MCPServerRuntimeInfo;
+      readme?: string;
       created_at?: string;
       updated_at?: string;
     }
@@ -561,6 +562,7 @@ export type MCPServer =
       enable: boolean;
       extra_args: MCPServerExtraArgsHttp;
       runtime_info?: MCPServerRuntimeInfo;
+      readme?: string;
       created_at?: string;
       updated_at?: string;
     }
@@ -571,6 +573,7 @@ export type MCPServer =
       enable: boolean;
       extra_args: MCPServerExtraArgsStdio;
       runtime_info?: MCPServerRuntimeInfo;
+      readme?: string;
       created_at?: string;
       updated_at?: string;
     };