Add redirects for renamed AI docs pages (#1971)

* Add redirects for docs/ai/plugin and docs/ai/opencode-subagent

Agent-Logs-Url: https://github.com/sveltejs/svelte.dev/sessions/e0b824eb-b483-4d4f-b414-1630d5e47b41

Co-authored-by: paoloricciuti <26281609+paoloricciuti@users.noreply.github.com>

* Update apps/svelte.dev/src/hooks.server.js

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: paoloricciuti <26281609+paoloricciuti@users.noreply.github.com>
Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>

Author: 3 people

apps/svelte.dev/src/hooks.server.js

@@ -73,6 +73,14 @@ export async function handle({ event, resolve }) {
 		redirect(308, event.url.pathname.replace('/docs/mcp', '/docs/ai'));
 	}
 
+	// Redirect from old ai docs paths to new paths
+	if (event.url.pathname === '/docs/ai/plugin') {
+		redirect(307, '/docs/ai/claude-plugin');
+	}
+	if (event.url.pathname === '/docs/ai/opencode-subagent') {
+		redirect(307, '/docs/ai/subagent');
+	}
+
 	// Best effort to redirect from Svelte 3 tutorial to new tutorial
 	if (event.url.pathname.startsWith('/tutorial/') && event.url.pathname.split('/').length === 2) {
 		redirect(307, event.url.pathname.replace('/tutorial/', '/tutorial/svelte/'));