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/import-method-dialog.tsx

@@ -1,7 +1,7 @@
-import { ClipboardPaste, FileUp, X } from "lucide-react";
+import { ClipboardPaste, FileUp } from "lucide-react";
 import { useCallback, useEffect, useRef, useState } from "react";
 import { Button } from "./ui/button.js";
-import { Dialog } from "./ui/dialog.js";
+import { Dialog, DialogHeader } from "./ui/dialog.js";
 
 interface ImportMethodDialogProps {
 	open: boolean;
@@ -41,18 +41,7 @@ export function ImportMethodDialog({
 
 	return (
 		<Dialog open={open} onClose={handleClose} className="w-80">
-			<div className="mb-4 flex items-center justify-between">
-				<h2 className="font-semibold text-lg">Import Encounter</h2>
-				<Button
-					type="button"
-					variant="ghost"
-					size="icon-sm"
-					onClick={handleClose}
-					className="text-muted-foreground"
-				>
-					<X className="h-4 w-4" />
-				</Button>
-			</div>
+			<DialogHeader title="Import Encounter" onClose={handleClose} />
 			{mode === "pick" && (
 				<div className="flex flex-col gap-2">
 					<button