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/sync-websocket.js

@@ -0,0 +1,84 @@
+/* eslint-disable no-undef, no-console, @typescript-eslint/no-unused-vars */
+import ws from 'k6/ws';
+import { check, sleep } from 'k6';
+import { Rate, Counter, Trend } from 'k6/metrics';
+
+const errorRate = new Rate('errors');
+const messagesReceived = new Counter('ws_messages_received');
+const messagesSent = new Counter('ws_messages_sent');
+const connectTime = new Trend('ws_connect_time', true);
+
+const SYNC_URL = __ENV.SYNC_URL || 'ws://localhost:3050';
+
+export const options = {
+	stages: [
+		{ duration: '30s', target: 10 },
+		{ duration: '3m', target: 30 },
+		{ duration: '30s', target: 0 },
+	],
+	thresholds: {
+		errors: ['rate<0.10'],
+		ws_connect_time: ['p(95)<1000'],
+	},
+};
+
+export default function () {
+	const url = `${SYNC_URL}/ws`;
+
+	const startTime = Date.now();
+	const res = ws.connect(url, {}, function (socket) {
+		const connected = Date.now() - startTime;
+		connectTime.add(connected);
+
+		socket.on('open', () => {
+			// Send a sync handshake (collection subscription)
+			const handshake = JSON.stringify({
+				type: 'subscribe',
+				collections: ['tasks', 'events', 'contacts'],
+				userId: `loadtest-vu-${__VU}`,
+				lastSyncTimestamp: new Date(Date.now() - 60000).toISOString(),
+			});
+			socket.send(handshake);
+			messagesSent.add(1);
+		});
+
+		socket.on('message', (data) => {
+			messagesReceived.add(1);
+
+			// Parse and validate sync messages
+			try {
+				const msg = JSON.parse(data);
+				check(msg, {
+					'has type field': (m) => m.type !== undefined,
+				});
+			} catch (_) {
+				// Binary or non-JSON message
+			}
+		});
+
+		socket.on('error', (e) => {
+			errorRate.add(true);
+			console.error(`WS error VU ${__VU}: ${e.error()}`);
+		});
+
+		// Keep connection alive for 10-30 seconds (simulates real user session)
+		const sessionDuration = Math.random() * 20 + 10;
+
+		// Send periodic sync pings
+		const pingInterval = setInterval(() => {
+			socket.send(JSON.stringify({ type: 'ping' }));
+			messagesSent.add(1);
+		}, 5000);
+
+		sleep(sessionDuration);
+		clearInterval(pingInterval);
+		socket.close();
+	});
+
+	const ok = check(res, {
+		'WS connection status is 101': (r) => r && r.status === 101,
+	});
+	errorRate.add(!ok);
+
+	sleep(Math.random() * 2 + 1);
+}