Migrate from mypy to pyright and clean up type annotations

[MaxDall]

Replaced mypy with pyright for type checking. While migrating, we stumbled across a handful of actual bugs and misconceptions hiding behind # type: ignore comments — so we fixed those instead of carrying them over.

Notable fixes along the way:

• Overload signatures in base_parser.py, regex.py, and parser/data.py were tightened
• JSONFile and its subclass dropped @dataclass in favor of explicit __init__, resolving a field type invariance issue cleanly
• Omit unnecessarily joining the pool in the CCNewsCrawler

Almost all # type: ignore comments are gone. The two that remain are intentional: one suppresses a third-party stubs incompatibility (warcio/urllib3), the other marks an intentionally invalid API call in a test.

Update: Maybe heading for ty [1] right away is the better choice here.