Application tools receive the runtime UnifiedActionContext, but caller-
supplied options['metadata'] (tenant/workspace/page/draft scoping the
host passes per run) never reached context->metadata — tools only saw
runtime-managed keys, so every host needed a side-channel to scope tool
behaviour. process() now merges caller metadata into the context each
turn: caller values refresh stale persisted copies of the same keys,
runtime keys (ai_native, conversation_context_metrics) use distinct
names and are unaffected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>