Schema validation for pathogen.json does not reject unknown fields or catch typos

The JSON schema (v3.0.0) used to validate pathogen.json files for Nextclade datasets is too permissive: adding unexpected properties (extra fields) or minor typos in key names does not trigger validation errors. As a result, malformed pathogen.json files can be accepted silently, leading to downstream misbehavior or confusing data issues. For example, the EV-D68 dataset included a misspelling in the `penalityGapOpen` field that was not detected. I attached a screen recording demonstrating the problem. Autofill suggestions work, and some fields (e.g., `gapAlignmentSide`) are validated for format, but extra keys or misspelled properties are neither highlighted nor cause the file to fail validation. https://github.com/user-attachments/assets/c027475e-4360-46ef-aad2-fa7cb2e8265d