chore: update relevance scoring

[developerfred]

in content evaluator to distinguish skipped evaluations

• Modify relevance scoring to use - for skipped evaluations or fixed relevance multipliers.
• Adjust reward calculation to handle - relevance scores appropriately.
• Ensure type safety by allowing relevance to be either a number or string (-).
• Update comments for clarity on the new relevance scoring system.

Resolves #113