v0.1.30 — has_document_id chips + open document

Added

• Data Explorer document_id chips: All / with doc / no doc (?has_document_id=true|false)
• Observation detail: clickable document_id + open document → (/data?tab=documents&q=…)
• Dashboard document_id coverage bar → ?has_document_id=true

Changed

• Engine / feature → 0.1.30