test: add integration test suite + canary deployment script

Integration tests:
- internal/serviceadapter/integration_test.go (8 test cases)
- Tests real gateway: health, routing, 404s, auth flow
- Configurable via GATEWAY_URL, TEST_JWT_TOKEN, SKIP_AUTH_TESTS

Canary deployment script:
- scripts/test-canary.sh: scale→1, test, scale→N on pass
- Keeps 1 pod for debugging on test failure
- Supports custom NAMESPACE, DEPLOYMENT, REPLICAS

Usage:
- Local: ./scripts/test-integration.sh
- Production: GATEWAY_URL=https://api.riotpiao.com ./scripts/test-integration.sh
- Canary: ./scripts/test-canary.sh

Added INTEGRATION_TESTS.md with full documentation.

scripts/test-canary.sh

@@ -0,0 +1,54 @@
+#!/bin/bash
+# Canary deployment test:
+# 1. Scale to 1 pod
+# 2. Wait for pod to be ready
+# 3. Run integration tests
+# 4. If pass, scale to 3 pods
+# 5. If fail, keep at 1 pod for debugging
+
+set -e
+
+NAMESPACE=${NAMESPACE:-api}
+DEPLOYMENT=${DEPLOYMENT:-api-gateway}
+REPLICAS=${REPLICAS:-3}
+GATEWAY_URL=${GATEWAY_URL:-https://api.riotpiao.com}
+
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+echo "CANARY TEST: $DEPLOYMENT"
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+
+# Step 1: Scale to 1 pod
+echo "[1/4] Scaling to 1 canary pod..."
+kubectl -n "$NAMESPACE" scale deploy "$DEPLOYMENT" --replicas=1
+kubectl -n "$NAMESPACE" rollout status deploy "$DEPLOYMENT" --timeout=2m
+
+echo "[2/4] Waiting for pod to be ready..."
+sleep 5
+
+# Step 2: Run integration tests
+echo "[3/4] Running integration tests..."
+export GATEWAY_URL="$GATEWAY_URL"
+export SKIP_AUTH_TESTS=true
+export TEST_TIMEOUT=30
+
+if ! go test -tags integration -v ./internal/serviceadapter -run TestIntegration; then
+    echo ""
+    echo "❌ Integration tests FAILED"
+    echo "Keeping 1 canary pod for debugging."
+    echo "Pod logs:"
+    kubectl -n "$NAMESPACE" logs -l app="$DEPLOYMENT" --tail=50
+    exit 1
+fi
+
+echo ""
+echo "✅ Integration tests PASSED"
+
+# Step 3: Scale back to full replicas
+echo "[4/4] Scaling back to $REPLICAS pods..."
+kubectl -n "$NAMESPACE" scale deploy "$DEPLOYMENT" --replicas="$REPLICAS"
+kubectl -n "$NAMESPACE" rollout status deploy "$DEPLOYMENT" --timeout=5m
+
+echo ""
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+echo "✅ Canary test complete. Rollout successful."
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"

scripts/test-integration.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+# Run integration tests against real gateway
+# Usage:
+#   ./scripts/test-integration.sh                           # Test local gateway
+#   GATEWAY_URL=https://api.riotpiao.com ./scripts/test-integration.sh  # Test production
+
+set -e
+
+GATEWAY_URL=${GATEWAY_URL:-http://localhost:8080}
+SKIP_AUTH_TESTS=${SKIP_AUTH_TESTS:-true}
+TEST_TIMEOUT=${TEST_TIMEOUT:-10}
+
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+echo "Integration Tests"
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+echo "Gateway URL:     $GATEWAY_URL"
+echo "Skip Auth Tests: $SKIP_AUTH_TESTS"
+echo "Timeout:         ${TEST_TIMEOUT}s"
+echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+
+export GATEWAY_URL
+export SKIP_AUTH_TESTS
+export TEST_TIMEOUT
+
+go test -tags integration -v ./internal/serviceadapter -run TestIntegration