Add C# MCP Server Development collection (#323)

* Add C# MCP Server Development collection

- Add instructions for C# MCP server development best practices
- Add prompt for generating complete MCP server projects
- Add expert chat mode for C# MCP development assistance
- Add collection grouping all C# MCP resources together
- Update README files with new contributions

* Add applyTo field to C# MCP instructions

README.collections.md

@@ -17,12 +17,14 @@ Curated collections of related prompts, instructions, and chat modes organized a
 | ---- | ----------- | ----- | ---- |
 | [Azure & Cloud Development](collections/azure-cloud-development.md) | Comprehensive Azure cloud development tools including Infrastructure as Code, serverless functions, architecture patterns, and cost optimization for building scalable cloud applications. | 18 items | azure, cloud, infrastructure, bicep, terraform, serverless, architecture, devops |
 | [C# .NET Development](collections/csharp-dotnet-development.md) | Essential prompts, instructions, and chat modes for C# and .NET development including testing, documentation, and best practices. | 7 items | csharp, dotnet, aspnet, testing |
+| [C# MCP Server Development](collections/csharp-mcp-development.md) | Complete toolkit for building Model Context Protocol (MCP) servers in C# using the official SDK. Includes instructions for best practices, a prompt for generating servers, and an expert chat mode for guidance. | 3 items | csharp, mcp, model-context-protocol, dotnet, server-development |
 | [Clojure Interactive Programming](collections/clojure-interactive-programming.md) | Tools for REPL-first Clojure workflows featuring Clojure instructions, the interactive programming chat mode and supporting guidance. | 3 items | clojure, repl, interactive-programming |
 | [Database & Data Management](collections/database-data-management.md) | Database administration, SQL optimization, and data management tools for PostgreSQL, SQL Server, and general database development best practices. | 8 items | database, sql, postgresql, sql-server, dba, optimization, queries, data-management |
 | [DevOps On-Call](collections/devops-oncall.md) | A focused set of prompts, instructions, and a chat mode to help triage incidents and respond quickly with DevOps tools and Azure resources. | 5 items | devops, incident-response, oncall, azure |
 | [Frontend Web Development](collections/frontend-web-dev.md) | Essential prompts, instructions, and chat modes for modern frontend web development including React, Angular, Vue, TypeScript, and CSS frameworks. | 11 items | frontend, web, react, typescript, javascript, css, html, angular, vue |
 | [Java Development](collections/java-development.md) | Comprehensive collection of prompts and instructions for Java development including Spring Boot, Quarkus, testing, documentation, and best practices. | 12 items | java, springboot, quarkus, jpa, junit, javadoc |
 | [Power Apps Code Apps Development](collections/power-apps-code-apps.md) | Complete toolkit for Power Apps Code Apps development including project scaffolding, development standards, and expert guidance for building code-first applications with Power Platform integration. | 3 items | power-apps, power-platform, typescript, react, code-apps, dataverse, connectors |
+| [Power BI Development](collections/power-bi-development.md) | Comprehensive Power BI development resources including data modeling, DAX optimization, performance tuning, visualization design, security best practices, and DevOps/ALM guidance for building enterprise-grade Power BI solutions. | 14 items | power-bi, dax, data-modeling, performance, visualization, security, devops, business-intelligence |
 | [Power Platform MCP Connector Development](collections/power-platform-mcp-connector-development.md) | Complete toolkit for developing Power Platform custom connectors with Model Context Protocol integration for Microsoft Copilot Studio | 4 items | power-platform, mcp, copilot-studio, custom-connector, json-rpc |
 | [Project Planning & Management](collections/project-planning.md) | Tools and guidance for software project planning, feature breakdown, epic management, implementation planning, and task organization for development teams. | 17 items | planning, project-management, epic, feature, implementation, task, architecture, technical-spike |
 | [Security & Code Quality](collections/security-best-practices.md) | Security frameworks, accessibility guidelines, performance optimization, and code quality best practices for building secure, maintainable, and high-performance applications. | 6 items | security, accessibility, performance, code-quality, owasp, a11y, optimization, best-practices |