Make linting fail if rule is missing percentage

[Fahad Heylaal]

Background

• We have linting: https://featurevisor.com/docs/linting/
• Rules are defined with percentages: https://featurevisor.com/docs/features/#rules

Issue

If a rule is missing the percentage key, linting is not picking it up.

Where to look?

https://github.com/featurevisor/featurevisor/blob/main/packages/core/src/linter/featureSchema.ts#L71