Define organization label taxonomy and routing contract

[szmyty]

Summary

• publish the versioned canonical organization label catalog and JSON schemas
• classify the complete approved 30-label catalog into five opt-in overlays
• define required universal priority, type, area, coordination, and status labels
• add governed repository assignments and a deterministic .github reference projection
• document ownership, routing, collision, lifecycle, deprecation, removal, rollback, and private-repository behavior
• strengthen the organization work form and add local issue-template configuration
• validate the contract with a pinned, least-privilege GitHub Actions workflow

Ownership boundary

.github owns label meaning, overlay definitions, and repository assignments. Relay owns previewing and applying provider mutations and must consume a merged immutable revision. Pace may report adoption and drift but does not gain mutation authority.

This contract does not redefine Hygiene's broader machine-readable portfolio policy.

Safety

• universal labels cannot be disabled
• repository labels cannot redefine canonical names
• unknown overlays and version mismatches fail closed
• deletion is never inferred from absence
• the default removal policy is retain
• no credentials or repository write permissions are introduced

Validation

• python scripts/validate_labels.py
• python -m unittest discover --start-directory tests --verbose (9 tests)
• deterministic reference projection diff
• JSON and YAML parsing
• Python compilation
• git diff --check

Closes #8