added new adventure game

[vivek2004-sec]

Description

Adds the initial base version of a text-based choose-your-own-adventure game (adventure_game.py). Player picks a path at a fork in the road (left → river, right → bridge), each with branching outcomes and invalid-input handling. Intentionally kept small and open-ended so other contributors can extend it with new paths, endings, and mechanics — see linked issue.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code cleanup/refactoring

Related Issues

Closes #3205

Testing

Please describe the tests you've run to verify your changes:

• Manual testing
• Added automated tests
• Existing tests pass

Checklist

• My code follows the project's code style
• I have commented my code, particularly in hard-to-understand areas
• I have updated the README.md if needed
• My changes generate no new warnings
• I have tested my code locally
• New and existing tests pass with my changes

Screenshots (if applicable)

Add screenshots or demos of your changes if relevant.

[vivek2004-sec]

Heads up — this is intentionally a small, incomplete starting point! I wanted to get a basic branching structure in place (fork in the road → river/bridge paths) rather than build out a full game solo.
If you're looking for a beginner-friendly first contribution, feel free to open a PR adding:

A new choice/branch at an existing decision point
A brand new path or ending
Small improvements like input validation or replay-on-invalid-input instead of just printing an error

Would love to see this grow into a proper multi-path adventure with community input. Happy to review any additions!