Implement extendable architecture for atomic system

[octoshikari]

Add Type-Safe Generic System with Extensible Interfaces

Summary

Implements a comprehensive type system that provides full TypeScript type safety while maintaining 100% backward compatibility.

Key Features

• Generic Resource Schemas: Define custom resource types with full type inference
• Extensible Interfaces: Extend any service via TypeScript declaration merging
• FHIR Version Agnostic: Works with R4, R5, or custom resource types
• Full IDE Support: Autocomplete for resource types, search parameters, and custom methods

What's Changed

• Added src/types/ with generic schema system
• Updated all service interfaces with <Schema> generic parameter
• Created comprehensive examples and documentation
• Added manual release GitHub workflow with version selector

Example Usage

// Define your schema
declare module '@atomic-ehr/core' {
  interface CustomSchema {
    Patient: {
      resource: R4.IPatient;
      searchParams: { name?: string };
    };
  }

  interface Validator {
    validateWithAI(resource: any): Promise<ValidationResult>;
  }
}

// Get full type safety
const patient = await context.repository.create({
  resourceType: "Patient", // ✅ Autocomplete
  resource: { /* ✅ Typed as R4.IPatient */ }
});

await context.validator.validateWithAI(patient); // ✅ Custom method available