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>

services/mana-auth/src/routes/auth.ts

@@ -9,6 +9,7 @@ import { Hono } from 'hono';
 import type { AuthUser } from '../middleware/jwt-auth';
 import type { BetterAuthInstance } from '../auth/better-auth.config';
 import type { SecurityEventsService, AccountLockoutService } from '../services/security';
+import type { SignupLimitService } from '../services/signup-limit';
 import type { Config } from '../config';
 import { sourceAppStore, passwordResetRedirectStore } from '../auth/stores';
 
@@ -16,15 +17,37 @@ export function createAuthRoutes(
 	auth: BetterAuthInstance,
 	config: Config,
 	security: SecurityEventsService,
-	lockout: AccountLockoutService
+	lockout: AccountLockoutService,
+	signupLimit: SignupLimitService
 ) {
 	const app = new Hono<{ Variables: { user: AuthUser } }>();
 
 	// ─── Registration ────────────────────────────────────────
 
+	// ─── Signup Status (public) ─────────────────────────────
+
+	app.get('/signup-status', async (c) => {
+		const status = await signupLimit.getStatus();
+		return c.json(status);
+	});
+
 	app.post('/register', async (c) => {
 		const body = await c.req.json();
 
+		// Check daily signup limit
+		const limitCheck = await signupLimit.checkLimit();
+		if (!limitCheck.allowed) {
+			return c.json(
+				{
+					error: 'Registration limit reached',
+					message: 'Das tägliche Registrierungslimit ist erreicht. Versuche es morgen wieder.',
+					spotsRemaining: 0,
+					resetsAt: limitCheck.resetsAt,
+				},
+				429
+			);
+		}
+
 		// Store source app URL for email verification redirect
 		if (body.sourceAppUrl && body.email) {
 			sourceAppStore.set(body.email, body.sourceAppUrl);