Activity spinner (spikeball) freezes while the turn is still actively processing

Bug: The activity indicator (the animated spikeball) stops animating mid-turn while the assistant is still actively working and streaming output. The visual state desyncs from the actual processing state.

Impact: It becomes impossible to tell whether the agent is still running or has stalled/completed. Users either wait unnecessarily on a turn that is actually done, or assume it is frozen and interrupt work that is still in progress.

Repro: Long-running turns that include tool calls (file edits, shell commands, deploys). The spinner freezes partway through while text output continues afterward.

Expected: Spinner animates for the full duration the turn is actively processing, and stops only when the turn is genuinely idle/complete.

Environment: Claude Code on Windows.