[shrijayan]

Adds a MkDocs Material site for https://shrijayan.github.io/opencode-python-sdk/.

• Custom palette (paper/ink, amber accent, teal links), Fraunces + IBM Plex Sans + JetBrains Mono, light/dark/auto toggle
• Hand-built landing page: hero with install command, sync/async tabs with code annotations, feature grid, version chip read from the package
• Getting started, 10 guides, project pages (how it's built, contributing, versioning, security, changelog)
• API reference via mkdocstrings: clients, server launcher, every resource, pagination/streams, exceptions, and ~640 types split into domain pages, generated at build time by docs/hooks/types_reference.py
• llms.txt and llms-full.txt written on build
• Instant nav, search, copy buttons, social cards (CI), edit-this-page links
• .github/workflows/docs.yml: mkdocs build --strict on PRs, deploy to Pages on push to main
• docs dependency group; README, Documentation URL and CONTRIBUTING updated

src/ change is docstring-only: the generator now emits Raises: entries as Name: The server answered <status>. so griffe parses them (regenerated via python -m codegen).

Docs coverage gate

• tests/test_docs_coverage.py (runs in the existing pytest jobs) fails when a resource/method, opencode.__all__ name or opencode.types model is missing from the reference, when an exported class or its public members lack docstrings, when docs/guides/index.md misses a resource group, or when a guide references a method/type that no longer exists. Failures name the item and the file to edit.
• Ruff D1 enabled for the published package (it skips _private modules, which the test covers).
• Codegen now gives sub-resource accessors docstrings; missing docstrings in _exceptions.py and _server.py added.
• Rule documented in CONTRIBUTING.md.