observation completeness is a named hypothesis: every observation enters the shared history before the next block opens

Maintainer decision, landed by the after-compromise follow-up. The observation-side twin of effect completeness: the shared history at the opening of block k is the record of every observation the agent made before it (AfterCompromise.ObsComplete); knowledge the agent is entitled not to share with bidders still enters the record, through the twin market's redaction rather than a hidden channel. Under it every selection built from the agent's observations is a function of the shared history at the opening (obs_complete_public), the noise hypothesis applies to it, and the post-commission tracker bound covers every knowledge-acquiring violation (knowledge_motive_covered) — the knowledge motive adds nothing beyond the exchange rate. Its failure is the private-knowledge residual (Witness.private_selection); its interaction with reserved knowledge is the twin market's leakage residual. Filed beside effect completeness and description faithfulness; on item 101 as count integrity's observation side. Rejected alternative: leaving the private-knowledge residual open.