Function set_hidden_reinjection_active 

pub(crate) fn set_hidden_reinjection_active(block_id: &str, hidden: bool)

Called once, at the moment an AgentInputCommand is dispatched for a block — hidden: true starts (or extends) that block’s suppression window; hidden: false (any ordinary user turn) ends it. The tool_result continuation frames a hidden turn’s own tool-using reply produces never go through this path (they’re the CLI’s own stdout, not a fresh RPC), so they can’t accidentally clear it either — the same class of bug finding #7 fixed for the byte-scanning heuristic doesn’t exist here by construction.