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>

packages/application/src/toggle-concentration-use-case.ts

@@ -2,22 +2,16 @@ import {
 	type CombatantId,
 	type DomainError,
 	type DomainEvent,
-	isDomainError,
 	toggleConcentration,
 } from "@initiative/domain";
 import type { EncounterStore } from "./ports.js";
+import { runEncounterAction } from "./run-encounter-action.js";
 
 export function toggleConcentrationUseCase(
 	store: EncounterStore,
 	combatantId: CombatantId,
 ): DomainEvent[] | DomainError {
-	const encounter = store.get();
-	const result = toggleConcentration(encounter, combatantId);
-
-	if (isDomainError(result)) {
-		return result;
-	}
-
-	store.save(result.encounter);
-	return result.events;
+	return runEncounterAction(store, (encounter) =>
+		toggleConcentration(encounter, combatantId),
+	);
 }