Improve server startup readiness checks and navigation retries

Author: Copilot

src/lib/plugins/run-code-blocks/directives/screenshot.ts

@@ -58,7 +58,7 @@ function compile(steps: string, path: `${string}.png`, args: Args): string {
   let script = [
 `const puppeteer = require('puppeteer');
 const NAVIGATION_TIMEOUT = 180000;
-const MAX_NAVIGATION_RETRIES = 8;
+const MAX_NAVIGATION_RETRIES = 6;
 const RETRYABLE_NAVIGATION_ERRORS = [
   'Navigation timeout',
   'net::ERR_CONNECTION_REFUSED',

src/lib/plugins/run-code-blocks/directives/server/start.ts

@@ -21,15 +21,19 @@ interface Args {
   captureOutput?: boolean;
 }
 
-function extractURL(expect: Option<string>): Option<string> {
+function extractURL(expect: Option<string> | undefined): Option<string> {
   if (!expect) {
     return null;
   }
 
   let match = expect.match(/https?:\/\/[^\s"']+/);
 
   if (match) {
-    return match[0]!;
+    try {
+      return new URL(match[0]!).toString();
+    } catch {
+      return null;
+    }
   } else {
     return null;
   }