stop-hook-fires-on-user-wait-not-just-agent-stop

The session-stop hook fires repeatedly whenever the agent emits a short reply and awaits user input (e.g., a one-sentence clarifying question), not only when the agent actually terminates. This produced ~30 false-positive evaluations in a single brainstorming session, flooding context with irrelevant hook feedback. Root cause: the hook runtime interprets the agent going quiet as a stop event, regardless of whether a stop() call was made. Fix: the hook script must detect whether there is an outstanding tool-use or user-input-await state before evaluating completion gates.