Spam fix from v0.5.0 oversight:
- Staleness filter (default 600s, configurable per-toggle) drops backlog at dispatcher
entrance -- solves the "restart wave fires days of old events" problem definitively.
- Per-toggle cooldown_seconds (default 300s) throttles same (category, region) bursts.
- Per-(source, event_id) LRU dedup (10k entries) catches Central re-delivery.
- Renderer wired into _dispatch_toggles; toggle path now produces friendly mesh strings
with 150-byte UTF-8 hard cap and priority-order segment composition (no mid-char trunc).
- categories.py: stream_flood_warning / stream_high_water moved from weather -> geohazards
family (canonical toggle name = seismic in VALID_TOGGLES) to match the GUI family tab.
Verified end-to-end: 7200s-old events all dropped (100/0), fresh burst throttles to one
mesh broadcast per cooldown window (1/99), dedup catches duplicate event_ids (1/99).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
