feat: add TypeScript sample for Copilot Search API

[smita-MSFT]

What

Adds a TypeScript sample demonstrating how to use the Microsoft Graph Search API for Microsoft 365 Copilot scenarios.

The sample exposes a local Express-based REST API that performs semantic + keyword search against Microsoft 365 content using /beta/search/query.

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Features

• Express REST API server — exposes endpoints for search operations
• Microsoft Graph Search integration — calls /beta/search/query
• Hybrid search support — semantic + lexical query handling
• Path-based filtering — KQL-style path:"..." filtering
• Configurable pagination — supports pageSize parameter
• Azure AD authentication:
  • ClientSecretCredential (app-only)
  • DeviceCodeCredential (interactive login)
• Structured JSON responses — normalized output with searchHits and skipToken
• Environment-based configuration — .env driven credentials
• TypeScript implementation — aligned with existing typescript/samples pattern
• Clean project structure — src/ + dist/ build output

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Path

typescript/samples/copilot-search-api/

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How to Run

npm install
npm run build
npm start

Server runs at:

http://localhost:3000

Health check:

GET /health

Search endpoint:

POST /api/search

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Testing

Manually tested locally:

• TypeScript build successful (npm run build)
• Server runtime verified (npm start)
• /health endpoint validated
• /api/search endpoint validated
• Authentication verified with both credential types

[smita-MSFT]

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