Quarkus MCP Server Instructions (#96)

* Create quarkus-mcp-server-sse.instructions.md

* Fixed readme and metadata for instruction

instructions/quarkus-mcp-server-sse.instructions.md

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+---
+applyTo: '*'
+description: 'Quarkus and MCP Server with HTTP SSE transport development standards and instructions'
+---
+# Quarkus MCP Server
+
+Build MCP servers with Java 21, Quarkus, and HTTP SSE transport.
+
+## Stack
+
+- Java 21 with Quarkus Framework
+- MCP Server Extension: `mcp-server-sse`
+- CDI for dependency injection
+- MCP Endpoint: `http://localhost:8080/mcp/sse`
+
+## Quick Start
+
+```bash
+quarkus create app --no-code -x rest-client-jackson,qute,mcp-server-sse your-domain-mcp-server
+```
+
+## Structure
+
+- Use standard Java naming conventions (PascalCase classes, camelCase methods)
+- Organize in packages: `model`, `repository`, `service`, `mcp`
+- Use Record types for immutable data models
+- State management for immutable data must be managed by repository layer
+- Add Javadoc for public methods
+
+## MCP Tools
+
+- Must be public methods in `@ApplicationScoped` CDI beans
+- Use `@Tool(name="tool_name", description="clear description")`
+- Never return `null` - return error messages instead
+- Always validate parameters and handle errors gracefully
+
+## Architecture
+
+- Separate concerns: MCP tools → Service layer → Repository
+- Use `@Inject` for dependency injection
+- Make data operations thread-safe
+- Use `Optional<T>` to avoid null pointer exceptions
+
+## Common Issues
+
+- Don't put business logic in MCP tools (use service layer)
+- Don't throw exceptions from tools (return error strings)
+- Don't forget to validate input parameters
+- Test with edge cases (null, empty inputs)