docs: improve documentation for input/output types (#2864)
* docs: improve documentation for input/output types
Rewrite the Input and output types section in docs/python.md to
comprehensively document all supported types, wrapper types, and
structured output patterns.
Changes:
- Add primitive types reference table with JSON Schema mappings
- Document dict as input/output type
- Document Optional with both Optional[T] and T | None syntax
- Document list as both input and output type with examples
- Add structured output section covering cog.BaseModel and Pydantic BaseModel
- Add BaseModel field types reference table
- Add type limitations section (nested generics, unions, etc.)
- Fix AsyncIterator import (use typing.AsyncIterator, not cog)
- Remove incorrect claim that output class must be named Output
- Note that os.PathLike subclasses are accepted as cog.Path
- Regenerate docs/llms.txt
* docs: tighten input/output type wording accuracy
* docs: add markdownlint checks to mise and CI
Enforce baseline Markdown hygiene across tracked docs with markdownlint tasks and a CI gate, while keeping rule scope narrow to avoid broad formatting churn.
