feat: GPU offload, signup limit, load tests & capacity planning

- Route all AI workloads (Ollama, STT, TTS, Image Gen) to GPU server
  (192.168.178.11) via LAN instead of host.docker.internal
- Upgrade default model to gemma3:12b and max concurrent to 5
- Add daily signup limit service (MAX_DAILY_SIGNUPS env var)
- Add GET /api/v1/auth/signup-status public endpoint
- Add k6 load test suite (web-apps, auth, sync-websocket, ollama)
- Add capacity planning documentation
- Fix: add eslint-config to sveltekit-base and calendar Dockerfiles

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

load-tests/auth-api.js

@@ -0,0 +1,81 @@
+/* eslint-disable no-undef */
+import http from 'k6/http';
+import { check, sleep, group } from 'k6';
+import { Rate, Counter } from 'k6/metrics';
+
+const errorRate = new Rate('errors');
+const signupBlocked = new Counter('signup_blocked');
+
+const AUTH_URL = __ENV.AUTH_URL || 'http://localhost:3001';
+
+export const options = {
+	stages: [
+		{ duration: '30s', target: 5 },
+		{ duration: '2m', target: 20 },
+		{ duration: '30s', target: 0 },
+	],
+	thresholds: {
+		http_req_duration: ['p(95)<3000'],
+		errors: ['rate<0.10'],
+	},
+};
+
+// Generate unique test emails
+function testEmail(vuId, iter) {
+	return `loadtest_vu${vuId}_${iter}_${Date.now()}@test.invalid`;
+}
+
+export default function () {
+	// Weighted random: 70% health, 20% login attempts, 10% register
+	const roll = Math.random();
+
+	if (roll < 0.7) {
+		// Health check — lightweight, tests baseline
+		group('health', () => {
+			const res = http.get(`${AUTH_URL}/health`);
+			const ok = check(res, {
+				'health 200': (r) => r.status === 200,
+			});
+			errorRate.add(!ok);
+		});
+	} else if (roll < 0.9) {
+		// Login attempt with invalid credentials — tests lockout + DB
+		group('login', () => {
+			const res = http.post(
+				`${AUTH_URL}/api/v1/auth/login`,
+				JSON.stringify({
+					email: 'loadtest@nonexistent.invalid',
+					password: 'wrongpassword',
+				}),
+				{ headers: { 'Content-Type': 'application/json' } }
+			);
+			const ok = check(res, {
+				'login returns 401 or 429': (r) => r.status === 401 || r.status === 429,
+			});
+			errorRate.add(!ok);
+		});
+	} else {
+		// Registration — tests signup limit
+		group('register', () => {
+			const email = testEmail(__VU, __ITER);
+			const res = http.post(
+				`${AUTH_URL}/api/v1/auth/register`,
+				JSON.stringify({
+					email: email,
+					password: 'TestPassword123!',
+					name: `Load Test ${__VU}`,
+				}),
+				{ headers: { 'Content-Type': 'application/json' } }
+			);
+			const ok = check(res, {
+				'register returns 200 or 429': (r) => r.status === 200 || r.status === 429,
+			});
+			if (res.status === 429) {
+				signupBlocked.add(1);
+			}
+			errorRate.add(!ok);
+		});
+	}
+
+	sleep(Math.random() * 1.5 + 0.5);
+}