Tool contract 0.20.1

Grounding affordances (agent feedback #8 - an inference-error case study, filed at the user's request): war_current now carries an explicit period block (period_index, war_day, started_observed_at, period_end_nominal, week_end_nominal) so temporal claims cite fields instead of inferring; event-type lists are framed as schema-not-news; elixir_feedback accepts category 'other' and unknown categories get the valid list back.