feat: major cleanup + death alerts + idle detection + Discord webhooks

Cleanup:
- Removed 109 stale asset files from static/assets/ (was 122, now 13)
- Removed static/v2/ entirely (was duplicate of root assets)
- Removed dead dashboard code: DashboardView, Layout, GlobalStats,
  CharacterCard, CharacterGrid, VitalBar, TabContainer, CombatTab,
  RaresTab, MapTab, InventoryTab, global.css, MapTransformContext
- Removed recharts dependency (425KB chunk eliminated)
- CSS reduced from 17KB to 10KB
- Added deploy-frontend.sh script for one-command build+deploy
- Updated CLAUDE.md with combat_stats, share_*, dungeon_map events
  and React frontend architecture

Death alerts (frontend + backend):
- Frontend: DeathNotification component with red banner + sawtooth
  sound when vitae goes from 0 to >0
- Backend: detects vitae transition in vitals handler, sends Discord
  webhook to #aclog with "☠️ CHARACTER died! (vitae: X%)"
- Rate-limited: max 1 Discord alert per character per 5 minutes

Idle detection (backend):
- Background task runs every 60 seconds
- Detects: vt_state "default"/"idle" OR kph=0 while in combat/hunt
- Sends Discord webhook: "⚠️ CHARACTER appears idle (state: X, KPH: 0)"
- Auto-clears alert when character becomes active again
- No duplicate alerts for same idle period

Discord integration:
- DISCORD_ACLOG_WEBHOOK env var for webhook URL
- Used by both death alerts and idle detection
- Graceful fallback when not configured

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

deploy-frontend.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+# Build frontend and deploy to static/ — run from MosswartOverlord root
+set -e
+
+echo "Building frontend..."
+cd frontend && npm run build && cd ..
+
+echo "Syncing build output to static/..."
+rm -rf static/assets/
+cp static/_build/index.html static/index.html
+cp -r static/_build/assets/ static/assets/
+cp static/_build/sw.js static/sw.js 2>/dev/null || true
+rm -rf static/_build/
+
+echo "Done! $(ls static/assets/ | wc -l) asset files deployed."
+echo "Run 'git add static/ && git commit && git push' to deploy to server."