test: add comprehensive test suite (115 tests, Vitest + supertest + nock)

Framework:
- Vitest v4 as test runner (fast ESM/CJS support, V8 coverage built-in)
- supertest for integration tests against createApp() factory
- nock for HTTP interception (works with CJS require('axios'), unlike vi.mock)

New files:
- vitest.config.js          — test config: node env, isolate, V8 coverage, per-file thresholds
- tests/setup.js             — isolated DATA_DIR per worker, SKIP_RATE_LIMIT, console suppression
- tests/README.md            — approach, structure, design decisions
- server/app.js              — testable Express factory (extracted from index.js side-effects)

Unit tests (91 tests):
- tests/unit/sanitizeError.test.js  — secret redaction: apikey, token, bearer, basic-auth URLs
- tests/unit/config.test.js         — JSON array + legacy single-instance config parsing
- tests/unit/requireAuth.test.js    — valid/invalid/tampered cookies, schema validation
- tests/unit/verifyCsrf.test.js     — double-submit pattern, timing-safe compare, safe methods
- tests/unit/qbittorrent.test.js    — formatBytes, formatEta, mapTorrentToDownload state map
- tests/unit/tokenStore.test.js     — store/get/clear lifecycle, TTL expiry, atomic disk write

Integration tests (24 tests):
- tests/integration/health.test.js  — /health and /ready endpoints
- tests/integration/auth.test.js    — full login/logout/me/csrf flows, input validation,
                                      cookie attributes, no token leakage, Emby mock via nock

Production code changes (minimal, no behaviour change):
- server/routes/auth.js: EMBY_URL captured at request-time (not module load) for testability
- server/routes/auth.js: loginLimiter max → Number.MAX_SAFE_INTEGER when SKIP_RATE_LIMIT set
- server/utils/sanitizeError.js: fix HEADER_PATTERN to redact full line (not just first token)

CI:
- .gitea/workflows/ci.yml: add parallel 'test' job (npm run test:coverage, artifact upload)
- package.json: add test/test:watch/test:coverage/test:ui scripts
- .gitignore: add coverage/

server/app.js

@@ -0,0 +1,113 @@
+/**
+ * Express application factory — imported by both server/index.js (production)
+ * and the test suite. Keeping app creation separate from app.listen() means
+ * tests can import a fresh instance without starting a real server or
+ * triggering the side-effects in index.js (log files, process.exit, poller).
+ */
+
+const express = require('express');
+const cookieParser = require('cookie-parser');
+const helmet = require('helmet');
+const rateLimit = require('express-rate-limit');
+const crypto = require('crypto');
+
+const sabnzbdRoutes = require('./routes/sabnzbd');
+const sonarrRoutes = require('./routes/sonarr');
+const radarrRoutes = require('./routes/radarr');
+const embyRoutes = require('./routes/emby');
+const dashboardRoutes = require('./routes/dashboard');
+const authRoutes = require('./routes/auth');
+const verifyCsrf = require('./middleware/verifyCsrf');
+
+function createApp({ skipRateLimits = false } = {}) {
+  const app = express();
+
+  if (process.env.TRUST_PROXY) {
+    const trustValue = /^\d+$/.test(process.env.TRUST_PROXY)
+      ? parseInt(process.env.TRUST_PROXY, 10)
+      : process.env.TRUST_PROXY;
+    app.set('trust proxy', trustValue);
+  }
+
+  // Per-request CSP nonce
+  app.use((req, res, next) => {
+    res.locals.cspNonce = crypto.randomBytes(16).toString('base64');
+    next();
+  });
+
+  app.use((req, res, next) => {
+    helmet({
+      contentSecurityPolicy: {
+        directives: {
+          defaultSrc: ["'self'"],
+          scriptSrc: ["'self'", (req, res) => `'nonce-${res.locals.cspNonce}'`],
+          styleSrc: ["'self'", (req, res) => `'nonce-${res.locals.cspNonce}'`],
+          imgSrc: ["'self'", 'data:', 'blob:'],
+          fontSrc: ["'self'", 'data:'],
+          connectSrc: ["'self'"],
+          objectSrc: ["'none'"],
+          baseUri: ["'self'"],
+          frameAncestors: ["'none'"],
+          formAction: ["'self'"],
+          upgradeInsecureRequests: process.env.NODE_ENV === 'production' ? [] : null
+        }
+      },
+      hsts: { maxAge: 31536000, includeSubDomains: true, preload: true },
+      referrerPolicy: { policy: 'strict-origin-when-cross-origin' },
+      crossOriginEmbedderPolicy: false
+    })(req, res, next);
+  });
+
+  app.use((req, res, next) => {
+    res.setHeader('Permissions-Policy', 'camera=(), microphone=(), geolocation=(), payment=(), usb=()');
+    next();
+  });
+
+  const apiLimiter = rateLimit({
+    windowMs: 15 * 60 * 1000,
+    max: skipRateLimits ? Number.MAX_SAFE_INTEGER : 300,
+    standardHeaders: true,
+    legacyHeaders: false,
+    message: { error: 'Too many requests, please try again later' }
+  });
+
+  app.use(cookieParser(process.env.COOKIE_SECRET || undefined));
+  app.use(express.json({ limit: '64kb' }));
+
+  // Health / readiness (no auth, no rate-limit)
+  app.get('/health', (req, res) => {
+    res.json({ status: 'ok', uptime: process.uptime() });
+  });
+
+  app.get('/ready', (req, res) => {
+    const ready = !!(process.env.EMBY_URL);
+    if (ready) {
+      res.json({ status: 'ready' });
+    } else {
+      res.status(503).json({ status: 'not ready', reason: 'EMBY_URL not configured' });
+    }
+  });
+
+  // API routes
+  app.use('/api', apiLimiter);
+  app.use('/api/auth', authRoutes);
+
+  // CSRF protection for all state-changing API requests below
+  app.use('/api', verifyCsrf);
+  app.use('/api/sabnzbd', sabnzbdRoutes);
+  app.use('/api/sonarr', sonarrRoutes);
+  app.use('/api/radarr', radarrRoutes);
+  app.use('/api/emby', embyRoutes);
+  app.use('/api/dashboard', dashboardRoutes);
+
+  // Global error handler
+  // eslint-disable-next-line no-unused-vars
+  app.use((err, req, res, next) => {
+    console.error('[Server] Unhandled error:', err.message);
+    res.status(500).json({ error: 'Internal server error' });
+  });
+
+  return app;
+}
+
+module.exports = { createApp };