Contract 11.1.0

Timeline sessions and crossings carry an evidence version and observation time. elixir_timeline accepts evidence_item_id with bounded evidence_offset/evidence_limit and expected_evidence_version to read exact ordered canonical game references for a visible item. Evidence reads always preserve the read pointer. Sessions disclose unknown capture completeness and bounded anchors; a crossing names a game only when proved. Late arena proof keeps the original moment identity and is observed when attached. Additive; JSON API remains 3.0.0 (no mirrored Timeline operation).