test: add initial Cypress e2e test infrastructure

Smoke tests for verifying Cypress runs, plus basic API tests
for health and sessions endpoints.

cypress/e2e/smoke.cy.js

@@ -0,0 +1,58 @@
+/// <reference types="cypress" />
+
+/**
+ * Smoke test to verify that the Cypress test infrastructure is
+ * correctly installed and configured. These tests do NOT require
+ * the lovdata-chat stack to be running.
+ */
+describe('Cypress Infrastructure Smoke Test', () => {
+    it('should execute a basic assertion', () => {
+        expect(true).to.be.true;
+    });
+
+    it('should handle arrays and objects', () => {
+        const session = {
+            id: 'test-session-001',
+            status: 'running',
+            model: 'opencode/kimi-k2.5-free',
+        };
+
+        expect(session).to.have.property('id');
+        expect(session.status).to.eq('running');
+        expect(session.model).to.include('kimi');
+    });
+
+    it('should validate the allowed models whitelist structure', () => {
+        const allowedModels = [
+            {
+                id: 'opencode/kimi-k2.5-free',
+                display_name: 'Kimi K2.5',
+                provider: 'zen',
+                is_reasoning: false,
+                is_default: true,
+            },
+            {
+                id: 'anthropic/claude-sonnet-4-thinking',
+                display_name: 'Claude Sonnet 4 (Thinking)',
+                provider: 'zen',
+                is_reasoning: true,
+                thinking_budget_default: 10000,
+                thinking_budget_max: 50000,
+            },
+        ];
+
+        expect(allowedModels).to.have.length(2);
+
+        const defaultModel = allowedModels.find((m) => m.is_default);
+        expect(defaultModel).to.exist;
+        expect(defaultModel.id).to.eq('opencode/kimi-k2.5-free');
+
+        const reasoningModels = allowedModels.filter((m) => m.is_reasoning);
+        expect(reasoningModels).to.have.length(1);
+        expect(reasoningModels[0]).to.have.property('thinking_budget_default');
+        expect(reasoningModels[0]).to.have.property('thinking_budget_max');
+        expect(reasoningModels[0].thinking_budget_max).to.be.greaterThan(
+            reasoningModels[0].thinking_budget_default
+        );
+    });
+});