Add derivation diagnostics companion artifact

[sybapp]

What to build

Write feature derivation diagnostics beside Versioned Datasets so LuxAlgo ICT/SMC signal extraction failures are reproducible and auditable without polluting strategy-consumable features.

Acceptance criteria

• A Versioned Dataset may include a diagnostics companion artifact for feature derivation results.
• Diagnostics include derivation rule/version, aggregate counts, warnings, and representative unresolved examples.
• Unresolved direction, invalid zone geometry, and missing provenance are recorded without aborting the entire dataset write.
• Strategy-consumable features.json remains free of diagnostics-only records.
• Tests cover diagnostics output for at least one unresolved direction and one invalid zone geometry case.

Blocked by

• Derive directional Structure Event signals from LuxAlgo graphics #23