docs(contributing): add issue and pull request templates

[PalmaAnd]

New issues and pull requests do not ask for the information maintainers need, which leads to vague reports and inconsistent descriptions.

Proposed change

Add focused GitHub templates for bug reports, feature requests, and pull requests. Keep the prompts short and specific to this repository.

Acceptance criteria

• Bug reports ask for reproduction steps, expected behavior, and runtime details.
• Feature requests ask for the user problem and desired result.
• Pull requests explain the problem, solution, and verification.
• Blank issues remain available when none of the templates fit.

[PalmaAnd]

• Fix typo inside Style Guidlines.md