Problem

Sensei treats descriptions exceeding 1024 characters as Invalid (hard fail per agentskills.io spec). Waza's SpecDescriptionChecker only returns a StatusWarning and the HeuristicScorer has no Invalid adherence level.

Expected Behavior

• Add Invalid as a score level in the adherence enum
• Descriptions >1024 chars should return Invalid before any other scoring
• The scoring algorithm should short-circuit: if len(desc) > 1024 → Invalid

References

• spboyer/sensei references/scoring.md — scoring algorithm with Invalid level
• agentskills.io spec — 1024 char description constraint

Acceptance Criteria

• Invalid adherence level added
• Scorer returns Invalid for >1024 char descriptions
• Tests for the boundary (1024, 1025 chars)