NO-TICKET: chore(fossa): exclude example app from fossa scan

[SenNeonoveNoci]

This PR adds a new .fossa.yml configuration file to exclude example apps from Fossa scans.

Checklist

• My code follows the project's coding standards.
• I have run linters/formatters and fixed any issues.
• There are no merge conflicts.
• I have performed a self-review of my code.
• All new and existing tests pass locally.
• I have added license headers to all files.

Generative AI usage

• GAI was not used (or, no additional notation is required)
• Coder created a draft manually that was non-substantively modified by GAI (e.g., refactoring was performed by GAI on manually written code)
• GAI was used to create a draft that was subsequently customized or modified
• Code was generated entirely by GAI