Add MkDocs-based GitHub Pages documentation site

[Copilot]

GIMKit lacked a dedicated documentation page, limiting discoverability and onboarding. Adds a MkDocs documentation site (using the Material theme) deployable via GitHub Pages.

Changes

• mkdocs.yml — MkDocs configuration with Material theme, dark/light mode toggle, code copy buttons, and a structured nav
• docs/index.md — Home page with feature overview and design philosophy
• docs/installation.md — Installation instructions (standard and vLLM variant)
• docs/quickstart.md — Quick start guide with code examples
• docs/usage.md — Full usage guide covering masked tags, queries, accessing results, and vLLM backends
• docs/api.md — API reference tables and examples
• docs/requirements.txt — Pins mkdocs and mkdocs-material for CI
• .github/workflows/docs.yml — Installs MkDocs, runs mkdocs build --strict, and deploys site/ to GitHub Pages on push to main (path-filtered to docs/** and mkdocs.yml) and on workflow_dispatch
• pyproject.toml — Documentation URL updated to https://sculptai.github.io/GIMKit

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[Ki-Seki]

@copilot I mean you should not use complicated doc frameworks, but you have to use frameworks (eg. mkdocs). Choose a proper one and implement it.

[Copilot]

@copilot I mean you should not use complicated doc frameworks, but you have to use frameworks (eg. mkdocs). Choose a proper one and implement it.

Replaced the plain HTML/CSS approach with MkDocs (Material theme) in commit 2bdf744.

The setup is:

• mkdocs.yml — config with Material theme, dark/light mode toggle, code copy buttons
• docs/ — Markdown source files: index.md, installation.md, quickstart.md, usage.md, api.md
• docs/requirements.txt — pins mkdocs and mkdocs-material
• .github/workflows/docs.yml — runs mkdocs build --strict and deploys site/ to GitHub Pages

The site builds cleanly with mkdocs build --strict and site/ is already excluded via .gitignore.