feat: rules engine — priority config UI + worklist scoring

- Rules engine spec v2 (priority vs automation rules distinction)
- Priority Rules settings page with weight sliders, SLA config, campaign/source weights
- Collapsible config sections with dynamic headers
- Live worklist preview panel with client-side scoring
- AI assistant panel (collapsible) with rules-engine-specific system prompt
- Worklist panel: score display with SLA status dots, sort by score
- Scoring library (scoring.ts) for client-side preview computation
- Sidebar: Rules Engine nav item under Configuration

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

src/components/rules/collapsible-section.tsx

@@ -0,0 +1,56 @@
+import { useState } from 'react';
+import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
+import { faChevronDown, faChevronRight } from '@fortawesome/pro-duotone-svg-icons';
+import { cx } from '@/utils/cx';
+
+interface CollapsibleSectionProps {
+    title: string;
+    subtitle?: string;
+    badge?: string;
+    badgeColor?: string;
+    defaultOpen?: boolean;
+    children: React.ReactNode;
+}
+
+export const CollapsibleSection = ({
+    title,
+    subtitle,
+    badge,
+    badgeColor = 'text-brand-secondary',
+    defaultOpen = true,
+    children,
+}: CollapsibleSectionProps) => {
+    const [open, setOpen] = useState(defaultOpen);
+
+    return (
+        <div className="rounded-xl border border-secondary bg-primary overflow-hidden">
+            <button
+                onClick={() => setOpen(!open)}
+                className="flex w-full items-center justify-between px-5 py-3.5 hover:bg-primary_hover transition duration-100 ease-linear"
+            >
+                <div className="flex items-center gap-3">
+                    <FontAwesomeIcon
+                        icon={open ? faChevronDown : faChevronRight}
+                        className="size-3 text-fg-quaternary"
+                    />
+                    <div className="text-left">
+                        <div className="flex items-center gap-2">
+                            <span className="text-sm font-semibold text-primary">{title}</span>
+                            {badge && (
+                                <span className={cx('text-xs font-medium tabular-nums', badgeColor)}>
+                                    {badge}
+                                </span>
+                            )}
+                        </div>
+                        {subtitle && <p className="text-xs text-tertiary mt-0.5">{subtitle}</p>}
+                    </div>
+                </div>
+            </button>
+            {open && (
+                <div className="border-t border-secondary px-5 pb-4">
+                    {children}
+                </div>
+            )}
+        </div>
+    );
+};