🏷️ Make Parameter.name typed as str instead of str | None

[YuriiMotov]

Description

On attempt to upgrade ty to 0.0.48+ it gives:

warning[unused-type-ignore-comment]: Unused blanket `type: ignore` directive
   --> typer/_click/core.py:924:38
    |
924 |         value = opts.get(self.name)  # type: ignore
    |                                      ^^^^^^^^^^^^^^
    |
help: Remove the unused suppression comment
921 |     def consume_value(
922 |         self, ctx: Context, opts: Mapping[str, Any]
923 |     ) -> tuple[Any, ParameterSource]:
    -         value = opts.get(self.name)  # type: ignore
924 +         value = opts.get(self.name)
925 |         source = ParameterSource.COMMANDLINE
926 |
927 |         if value is None:

This is obviously false-negative. self.name is typed as str | None, so it can't be passed to opts.get() that accepts str.

While investigatig this I found out that Click recently updated the typing of Parameter.name to just str. See PR pallets/click#2805

So, why don't we do the same?

AI Disclaimer

Implemented with the help of Claude Opus 4.8 (1M context), then reviewed manually

Checklist

• This PR links to a GitHub Discussion for the proposed code change.
• I added tests for the change.
• The new or updated tests fail on the main branch and pass on this PR.
• Coverage stays at 100%.
• The documentation explains the change if needed.

(typing only, no tests needed)