fix: readability — solid dark backgrounds on all chat cards (v1.4.2)

Root cause: all chat card containers used rgba() with 0.2-0.4 opacity,
which becomes nearly transparent on Foundry v14 parchment chat bg.
Light text (white, cyan, yellow, green) was invisible on the result.

CSS fixes (solid dark backgrounds replacing transparent rgba):
- .panic-result: rgba(139,0,0,0.2) -> #1c0808 + color: #e0e0e0
- .panic-success: rgba(0,128,0,0.2) -> #081c08 + green text toned to #55ee55
- .panic-effect: rgba(0,0,0,0.4) -> #111111 + color: #e0e0e0
- .critical-injury: rgba(220,20,60,0.2) -> #1c080d + color: #e0e0e0
- .crit-effects/.crit-healing/.crit-recovery: rgba(0,0,0,0.3) -> #111111
- .time-limit: rgba(255,170,0,0.2) -> #1a1200

New CSS classes added (were missing entirely):
- .instability-result with dark bg, border, and sub-element rules
- .instability-no-effect, .instability-effect-text, .instability-auto-note
- .panic-auto (auto-applied row)
- .drug-gm-alert, .weapon-reload-chat

JS inline style fixes:
- Rest card: rgba(0,60,30,0.3) -> #0a1a0e (solid)
- Ammo empty card: rgba(80,20,0,0.3) -> #1a0800 (solid)
- Instability effect text: color:#333 (dark on dark) -> CSS class #d8d8d8
- Instability auto-note: color:#ffcc44 inline -> CSS class

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": "1.4.1",
+  "version": "1.4.2",
   "compatibility": {
     "minimum": 13,
     "verified": "14.359"