docs: add CLI usage and development workflow documentation

[CoolatMax]

Description

This PR adds missing CLI documentation for Nanoforge and provides a clear “how to use it” guide that shows every step required to develop a game correctly using the CLI.

The documentation is workflow-first and includes both a step-by-step development guide and a structured CLI command reference.

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What is the type of issue?

Documentation was missing.

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What is the issue?

The existing documentation did not contain sufficient information about how to use the Nanoforge CLI, including:

• The correct order of commands for development
• How to use the CLI end-to-end
• How CLI commands relate to the game development workflow

This made it difficult for new users to develop a game without inspecting the source code.

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What was added in this PR?

• A complete “how to use it” guide describing every step to develop a game correctly:
  1. Creating a new project
  2. Starting the development environment
  3. Developing the game
  4. Building the project for production
• A structured CLI command reference covering:
  • nf new
  • nf start
  • nf build
  • nf generate
  • nf install add
• Accurate documentation for CLI options, aligned with the current CLI implementation

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Where did you find it?

The missing documentation was identified while reviewing the existing docs/ content and comparing it against the available CLI commands and development workflow.

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Scope

• Documentation-only changes
• No changes to CLI behavior or source code

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Related issue

Closes #41

[MartinFillon]

Hi thanks for the pr, However your pr will not be accepted for the time being as it is not using the proper documentation language (markdown instead of rst) and doesn't add anything meaningfull and discuted. For example you talk about workflow-first developpement server. Which are factually false informations.

Moreover you invent options we dont have which makes me believe that what you brought here is generated by ai and that you are not a passionate developper wanting to help a small open source project.