fix: Ralph wizard uses file-based prompt to avoid screen escaping issues

- Add /api/sessions/:id/ralph-prompt/write endpoint to write prompt to @ralph_prompt.md
- Wizard now writes full prompt to file, then sends simple read command to Claude
- Fix session readiness check to wait for prompt character instead of notWorking flag
- Add E2E test infrastructure for ralph-loop workflow (port 3190)
- Add ralph-wizard-prod.mjs script for production testing

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

test/e2e/fixtures/server.fixture.ts

@@ -0,0 +1,53 @@
+/**
+ * Server fixture for E2E tests
+ * Manages WebServer lifecycle with proper startup/shutdown
+ */
+
+import { WebServer } from '../../../src/web/server.js';
+
+export interface ServerFixture {
+  server: WebServer;
+  port: number;
+  baseUrl: string;
+}
+
+/**
+ * Create and start a server fixture
+ * @param port - Port to run the server on
+ * @returns ServerFixture with server instance and connection info
+ */
+export async function createServerFixture(port: number): Promise<ServerFixture> {
+  const server = new WebServer(port);
+  await server.start();
+
+  // Wait for server to be fully ready
+  const maxWait = 10000;
+  const start = Date.now();
+  while (Date.now() - start < maxWait) {
+    try {
+      const response = await fetch(`http://localhost:${port}/api/status`);
+      if (response.ok) {
+        break;
+      }
+    } catch {
+      // Server not ready yet
+    }
+    await new Promise(r => setTimeout(r, 100));
+  }
+
+  return {
+    server,
+    port,
+    baseUrl: `http://localhost:${port}`,
+  };
+}
+
+/**
+ * Stop and cleanup a server fixture
+ * @param fixture - Server fixture to destroy
+ */
+export async function destroyServerFixture(fixture: ServerFixture): Promise<void> {
+  if (fixture.server) {
+    await fixture.server.stop();
+  }
+}