[E2E] Add Istio profile for E2E testing framework

[Xunzhuo]

Description

Add a new Istio profile to the E2E testing framework to test Semantic Router integration with Istio GW.

Background

The E2E testing framework introduced in #655 provides an extensible profile-based architecture. We need to add an Istio profile to test Semantic Router deployment and functionality in an Istio service mesh environment.

Tasks

• Create e2e/profiles/istio/ directory structure
• Implement Profile interface for Istio
  • Setup: Deploy Istio control plane and data plane
  • Setup: Deploy Semantic Router with Istio sidecar injection
  • Setup: Configure Istio VirtualService and DestinationRule
  • Teardown: Clean up Istio resources
• Implement test cases:
  • Basic health check with Istio sidecar
  • Traffic routing through Istio gateway
  • mTLS verification
  • Request tracing and observability
• Add documentation for Istio profile usage
• Update CI workflow to run Istio tests

Implementation Details

Profile Structure

type Profile struct {
    verbose bool
}

func (p *Profile) Setup(ctx context.Context, opts *framework.SetupOptions) error {
    // 1. Deploy Istio using istioctl or Helm
    // 2. Enable sidecar injection for namespace
    // 3. Deploy Semantic Router
    // 4. Configure Istio resources (VirtualService, Gateway, etc.)
}

Test Cases

1. Istio Sidecar Health Check: Verify Envoy sidecar is injected and healthy
2. Traffic Routing: Test request routing through Istio ingress gateway
3. mTLS Verification: Verify mutual TLS between services
4. Observability: Check distributed tracing and metrics collection

Acceptance Criteria

• Istio profile can be run with make e2e-test PROFILE=istio
• All test cases pass successfully
• Documentation is complete and clear
• CI integration works correctly

References

• E2E Framework PR: [Feat] Add automate e2e test framework for extensible integration tests #655
• Istio Documentation: https://istio.io/latest/docs/
• E2E Framework README: e2e/README.md

Related Issues

Part of the E2E testing framework expansion effort.

[Xunzhuo]

/area test-and-release
/priority P2
/label enhancement
/label e2e
/label help wanted

[asaadbalum]

/assign