Lint with ruff, pyright and mypy the examples and extra folders

[amenasria]

This PR adds:

• A precommit hook running ruff, pyright and mypy on commit modifications.
• A CI workflow running ruff, pyright and mypy on all files in the folders. It does not run on the examples folder yet

The folders we're linting are:

• examples/
• src/mistralai_private/extra/
• src/mistralai_private/_hooks/

[jean-malo]

@amenasria why not a makefile and / or uv scripts like in our other repos?

[amenasria]

@jean-malo I want to avoid using both uv and poetry, we'll move those when we'll move to uv.

For Makefile idk it would be weird to have that here.

[amenasria]

For now we've been droppping bash files, so I'm keeping the bash files going.