feat: Showing Off mechanic (v1.6.2)

Every roll dialog now has a gold SHOWING OFF button:
- Each click posts a big gold fanfare chat message + plays a WebAudio arpeggio
- Reduces the dice pool by 1 per click (floor: 1d6)
- Total dice display turns gold and shows the penalty
- Immediately increments actor system.details.showingOff tally
- At exactly 20 pts: public milestone broadcast with GM alert
- Finance tab: gold SHOWING OFF hero panel shows career total (editable)
- Hourly PC Status Report now includes Showing Off tally (yellow at >0, orange at 10+, red at 20+)
- template.json: showingOff: 0 added to character.details
- _playShowingOffFanfare(): ascending C-major arpeggio via WebAudio API

system.json

@@ -2,7 +2,7 @@
   "id": "zero-engine",
   "title": "Zero Engine (SLA Industries)",
   "description": "A basic game system for SLA Industries using the Zero Engine rules.",
-  "version": "1.6.1",
+  "version": "1.6.2",
   "compatibility": {
     "minimum": 13,
     "verified": "14.359"