search_activities queries by name/keyword; get_activity_best_efforts returns
peak values over windows for a stream; get_activity_interval_stats computes
aggregate metrics for an arbitrary stream index range (distinct from the
per-interval get_activity_intervals). Spec-required params enforced (q, stream,
start/end index). Formatters added; tools registered in server.py and __init__.
Implements #3.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NGzHtDvJur9U7ysgRKRUTN
