Générateur de classes depuis JSON

You are an experienced full-stack web developer. Build a web tool called "Générateur de classes JSON" that meets the requirements below.

## Goal

Build a tool that generates C#, Java, Python and TypeScript model classes from a JSON sample.

## Core features

- Choose C#, Java, Python dataclasses or TypeScript interfaces
- Create separate classes for nested objects
- Infer array element types
- Set the root class name
- Apply each language's naming conventions

## Inputs

- JSON sample
- Target language and root class name

## Outputs

- Generated code
- Summary of inferred types

## Edge cases and handling rules

- Treat null values as nullable types
- Merge differing keys across array elements
- Handle keys that clash with reserved words
- Keep original names for keys with digits or hyphens via serialization attributes

## Implementation requirements

- Build it as a single page (HTML, CSS, JavaScript) that runs entirely in the browser, and never send the user's input to a server.
- Make the UI responsive and easy to use on mobile; label every input and keep everything keyboard accessible.
- Add a Copy button for results and show clear, friendly error messages for invalid input.
- Keep the core logic in functions separate from the UI so it can be unit-tested.

## Definition of done (test cases)

- {"id":1,"name":"a"} gives int Id and string Name in C#
- Nested objects become separate classes
- Empty arrays become lists of object/any

First outline your implementation plan in at most five lines, then write the complete code, and finally explain how to check the test cases above.

---
name: build-json-class-generator
description: Use when building or changing a Générateur de classes JSON tool. Build a tool that generates C#, Java, Python and TypeScript model classes from a JSON sample.
---

# Build: Générateur de classes JSON

## Goal

Build a tool that generates C#, Java, Python and TypeScript model classes from a JSON sample.

## Workflow

1. Review the required features, inputs and outputs below and ask about anything missing first.
2. Implement the core logic as pure functions separate from the UI.
3. Check the logic against the test cases in the verification list.
4. Build a responsive UI with an input form, a result area and a Copy button.
5. Reproduce each edge case listed under Rules and refine the error messages.

## Core features

- Choose C#, Java, Python dataclasses or TypeScript interfaces
- Create separate classes for nested objects
- Infer array element types
- Set the root class name
- Apply each language's naming conventions

## Inputs

- JSON sample
- Target language and root class name

## Outputs

- Generated code
- Summary of inferred types

## Rules

- Treat null values as nullable types
- Merge differing keys across array elements
- Handle keys that clash with reserved words
- Keep original names for keys with digits or hyphens via serialization attributes
- Build it as a single page (HTML, CSS, JavaScript) that runs entirely in the browser, and never send the user's input to a server.

## Verification

- [ ] {"id":1,"name":"a"} gives int Id and string Name in C#
- [ ] Nested objects become separate classes
- [ ] Empty arrays become lists of object/any