Fix CI failures for backend and e2e test jobs

Replace astral-sh/setup-uv action with direct curl install to avoid
Node.js 18 incompatibility (setup-uv v6+ requires Node 20+). Change
e2e test API host port from 8000 to 8100 to avoid conflict with
existing service on the CI runner.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/e2e/global-setup.ts

@@ -4,7 +4,7 @@ import { dirname, resolve } from 'node:path'
 import { fileURLToPath } from 'node:url'
 
 const __dirname = dirname(fileURLToPath(import.meta.url))
-const API_BASE = 'http://localhost:8000/api/v1'
+const API_BASE = 'http://localhost:8100/api/v1'
 const COMPOSE_FILE = resolve(__dirname, '../../docker-compose.test.yml')
 const COMPOSE = `docker compose -p nuzlocke-test -f ${COMPOSE_FILE}`
 const FIXTURES_PATH = resolve(__dirname, '.fixtures.json')
@@ -48,7 +48,7 @@ export default async function globalSetup() {
 
   // 2. Wait for API to be healthy
   console.log('[setup] Waiting for API to be ready...')
-  await waitForApi('http://localhost:8000/')
+  await waitForApi('http://localhost:8100/')
 
   // 3. Run migrations
   run(`${COMPOSE} exec -T test-api alembic -c /app/alembic.ini upgrade head`)