Add comprehensive Kubernetes/AKS deployment article

[Copilot]

This PR creates a comprehensive article on deploying .NET Aspire applications to Kubernetes clusters, addressing the specific requirements outlined in issue #885.

Changes made

New article: docs/deployment/kubernetes-deployment.md

• Three deployment approaches: Aspir8 tool, .NET Aspire 9.3+ built-in publishing, and manual YAML creation
• Prerequisites section with links to AKS, Docker Desktop, and minikube setup guides (no dedicated cluster creation instructions as requested)
• Step-by-step instructions for each deployment method with code examples
• Visual Studio Code integration showing how existing Kubernetes tools work seamlessly with .NET Aspire
• Production considerations covering service discovery, secrets management, and health checks
• Troubleshooting section with common issues and debugging commands

Updated documentation structure

• Table of contents (docs/toc.yml): Added new Kubernetes deployment article under Deploy section
• Deployment overview (docs/deployment/overview.md): Updated to reference the comprehensive new article

Key features addressed from issue requirements

✅ Links to existing AKS documentation - No dedicated cluster creation section, points to Microsoft docs
✅ Hand-rolling K8S YAML files - Complete section with example manifests and kubectl commands
✅ Aspir8 configuration/deployment - Detailed walkthrough of the recommended approach
✅ Visual Studio Code Kubernetes extension - Workflow integration showing existing tools work with .NET Aspire

Technical accuracy

• Uses actual .NET Aspire 9.3 Kubernetes publishing features (PublishAsKubernetesService, AddKubernetesEnvironment)
• References current Aspir8 commands (aspirate init, aspirate generate, aspirate apply)
• Includes proper kubectl commands and realistic YAML examples
• Follows Microsoft Writing Style Guide with active voice and imperative mood

The article provides comprehensive coverage for both beginners and advanced users, emphasizing that existing Kubernetes tooling continues to work effectively with .NET Aspire applications.

Fixes #885.

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Internal previews

📄 File	🔗 Preview link
docs/deployment/kubernetes-deployment.md	docs/deployment/kubernetes-deployment
docs/deployment/overview.md	docs/deployment/overview
docs/toc.yml	docs/toc