chore(vite): pin dev server to port 5174

Enable strictPort so local dev always matches the frontend Docker proxy setup.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -34,3 +34,4 @@ coverage
 .env
 .env.*
 !.env.example
+!.env.docker.example

vite.config.ts

@@ -16,6 +16,8 @@ export default defineConfig({
     },
   },
   server: {
+    port: 5174,
+    strictPort: true,
     proxy: {
       '/api': {
         target: 'http://127.0.0.1:3000',