Add jsinspect-plus structural duplication gate, extract shared helpers

Add jsinspect-plus (AST-based structural duplication detector) to pnpm
check with threshold 50 / min 3 instances. Fix all findings:

- Extract condition icon/color maps to shared condition-styles.ts
- Extract useClickOutside hook (5 components)
- Extract dispatchAction + resolveAndRename in use-encounter
- Extract runEncounterAction in application layer (13 use cases)
- Extract findCombatant helper in domain (9 functions)
- Extract TraitSection in stat-block (4 trait rendering blocks)
- Extract DialogHeader in dialog.tsx (4 dialogs)

Net result: -263 lines across 40 files.

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

apps/web/src/components/ui/dialog.tsx

@@ -1,5 +1,7 @@
+import { X } from "lucide-react";
 import { type ReactNode, useEffect, useRef } from "react";
 import { cn } from "../../lib/utils.js";
+import { Button } from "./button.js";
 
 interface DialogProps {
 	open: boolean;
@@ -48,3 +50,22 @@ export function Dialog({ open, onClose, className, children }: DialogProps) {
 		</dialog>
 	);
 }
+
+export function DialogHeader({
+	title,
+	onClose,
+}: Readonly<{ title: string; onClose: () => void }>) {
+	return (
+		<div className="mb-4 flex items-center justify-between">
+			<h2 className="font-semibold text-foreground text-lg">{title}</h2>
+			<Button
+				variant="ghost"
+				size="icon-sm"
+				onClick={onClose}
+				className="text-muted-foreground"
+			>
+				<X className="h-4 w-4" />
+			</Button>
+		</div>
+	);
+}