Add property-based fuzz testing for scoring module

[Mkalbani]

Description

The scoring module currently only has example-based unit tests. Add property-based tests (using proptest or quickcheck) to catch edge cases in score calculation, such as negative time deltas, hint-count overflow, or zero-duration sessions.

Acceptance Criteria

• proptest added as a dev-dependency
• Properties defined: score is never negative, score never exceeds the documented max, hint penalties are monotonic
• At least 5 distinct property tests covering the scoring formula's edge cases
• Any bugs found during implementation are fixed and documented in the PR description
• CI runs the property tests as part of the standard test suite

[Songu3020]

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.

[Songu3020]

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.

[grantfox-oss]

🦊 GrantFox — @Songu3020 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #29)
2. Your PR will be reviewed by the ThinknetCollective maintainers

Good luck! Track your progress on GrantFox.