Add TypeScript vector search quickstart with AZD infrastructure

[diberry]

Description

Add a TypeScript vector search quickstart sample and AZD (Azure Developer CLI) infrastructure for one-command deployment.

What's included

TypeScript sample (\TypeScript/)

• Complete vector search quickstart using \ edious\ (SQL Server driver) + @azure/identity\ + @azure/openai\
• DefaultAzureCredential auth for both Azure SQL and Azure OpenAI (no passwords/keys)
• Creates table with VECTOR(1536) column, generates embeddings, performs similarity search with \VECTOR_DISTANCE()\
• Quickstart-style README.md with setup instructions and expected output
• Node.js 20+, TypeScript strict mode

AZD infrastructure (\infra/\ + \�zure.yaml)

• Azure SQL Database with Azure AD-only authentication
• Azure OpenAI with text-embedding-3-small deployment
• User-assigned managed identity with RBAC role assignments
• \�zd up\ deploys everything in one command

Follows patterns from

• cosmos-db-vector-samples — same AZD + DefaultAzureCredential approach
• Existing \DotNet/\ samples in this repo — PascalCase directory naming

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com