Upgrade Biome to 2.4.7 and enable 54 additional lint rules

Add rules covering bug prevention (noLeakedRender, noFloatingPromises,
noImportCycles, noReactForwardRef), security (noScriptUrl, noAlert),
performance (noAwaitInLoops, useTopLevelRegex), and code style
(noNestedTernary, useGlobalThis, useNullishCoalescing, useSortedClasses,
plus ~40 more). Fix all violations: extract top-level regex constants,
guard React && renders with boolean coercion, refactor nested ternaries,
replace window with globalThis, sort Tailwind classes, and introduce
expectDomainError test helper to eliminate conditional expects.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/domain/src/__tests__/remove-combatant.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from "vitest";
 import { removeCombatant } from "../remove-combatant.js";
 import type { Combatant, Encounter } from "../types.js";
 import { combatantId, isDomainError } from "../types.js";
+import { expectDomainError } from "./test-helpers.js";
 
 // --- Helpers ---
 
@@ -92,10 +93,7 @@ describe("removeCombatant", () => {
 			const e = enc([A, B], 0, 1);
 			const result = removeCombatant(e, combatantId("nonexistent"));
 
-			expect(isDomainError(result)).toBe(true);
-			if (isDomainError(result)) {
-				expect(result.code).toBe("combatant-not-found");
-			}
+			expectDomainError(result, "combatant-not-found");
 		});
 	});