feat(champ): stream champion-spawn state to the sidecar board

Champion spawns have no ServUO EventSink, so add a fourth polled stream
(BridgeChamps) modeled on BridgeSweeps: enumerate every spawn each tick,
fold to a small record, and emit champ.update only on change. No core
patch — every field used is public.

Covers all three families via a `category` field:
  - champion: ChampionSpawn (type/level/kills/boss/cooldown ETA)
  - mini:     MiniChamp (type/level; auto-restarts, no kill counter)
  - sea:      BaseSeaChampion (a High Seas world-boss mobile, alive only
              while summoned; removed via champ.remove when slain)

Status folds to active/cooldown/dormant. A (re)connection clears the diff
cache so the next sweep re-emits the full board, rebuilding a sidecar that
restarted on its own. Transient entries leave via champ.remove.

Sidecar: a `champs` current-state table (one row per serial) fed by
champ.update (upsert) and champ.remove (delete), exposed at GET /champs as
the live board. New ChampSweepSeconds config (default 10s), wired into
[bridge reload/sweepnow/status. Documented in docs/INTEGRATION.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0114TpmrNW4wNXsHq5CR72jQ

overlay/Config/Bridge.cfg

@@ -19,6 +19,11 @@ StatSweepSeconds=30
 DecaySweepSeconds=60
 EconomySweepSeconds=300
 
+# Champion-spawn board poll. ChampionSpawn has no EventSink, so every spawn is diffed on
+# this interval to emit champ.update on any status/level/kills/boss change. The world holds
+# only a handful of spawns, so the pass is trivial; 5-10s is well within site tolerance.
+ChampSweepSeconds=10
+
 # Help-page queue poll. The in-game page queue has no EventSink, so it is diffed on this
 # interval to emit page.new / page.closed / page.updated. A few seconds is fine for a
 # support queue; the full open queue is also available on demand via pages.snapshot.