fix(settings, yjs, ux, ci): default settings, y-leveldb restart resilience, dashboard one-click open, delete error handling, Playwright CI

backend/src/routes/settings.ts

@@ -7,6 +7,13 @@ import { requireAuth } from '../auth/authMiddleware.js';
 import type { AuthService } from '../auth/AuthService.js';
 import { validateSettingsKey, validateSettingsValue } from '../utils/validation.js';
 
+/** Built-in default settings so the frontend never sees a 404 for known keys. */
+const DEFAULT_SETTINGS: Record<string, string> = {
+  'cad.unit': 'mm',
+  'cad.gridSize': '20',
+  'cad.scaleFactor': '1',
+};
+
 export function registerSettingsRoutes(fastify: FastifyInstance, db: DatabaseInterface, authService: AuthService) {
   // Get a single setting by key
   fastify.get('/api/settings/:key', async (request, reply) => {
@@ -15,8 +22,12 @@ export function registerSettingsRoutes(fastify: FastifyInstance, db: DatabaseInt
     const keyErr = validateSettingsKey(key);
     if (keyErr) return reply.code(400).send({ error: keyErr });
     const setting = db.getSetting(key);
-    if (!setting) return reply.code(404).send({ error: 'Setting not found' });
-    return setting;
+    if (setting) return setting;
+    // Return a default value for known CAD settings instead of 404
+    if (DEFAULT_SETTINGS[key] !== undefined) {
+      return { key, value: DEFAULT_SETTINGS[key], updated_at: new Date().toISOString() };
+    }
+    return reply.code(404).send({ error: 'Setting not found' });
   });
 
   // Create or update a setting (upsert)