Feature: Auto-documentation (generate docs from .http requests)

[cedric05]

Add auto-documentation generation to dothttp to produce Markdown/HTML/OpenAPI/Postman docs from .http requests and annotations. The feature should parse dothttp annotations (description, tags, params, examples) and generate comprehensive docs, plus optional watch mode and custom templates.

Goals:

• Allow generating quick API docs that stay in sync with requests
• Support multiple output formats: Markdown, HTML, OpenAPI 3.0, Postman collection
• Support annotations for descriptions, parameters, examples, and response schemas

Proposed CLI:

• dothttp users.http --docs --format=markdown --output=docs.md
• dothttp users.http --docs --format=openapi3 --output=openapi.json
• dothttp users.http --docs --watch --output=docs/

Acceptance criteria:

• Docs generation supports Markdown and HTML
• OpenAPI export maps routes, methods, params, and example bodies
• Configurable templates for branding
• VSCode command for generating docs with options UI

Implementation notes:

• Use Jinja2 for templating outputs
• Infer JSON schemas from example responses where possible
• Respect annotations in the .http files