Refactor App.tsx from god component to context-based architecture

Replace prop drilling with React context providers. App.tsx shrinks
from 427 lines to ~80 lines of pure layout. Components consume shared
state directly via 7 context providers instead of threading 50+ props.

Key changes:
- 7 context providers wrapping existing hooks (encounter, bestiary,
  player characters, side panel, theme, bulk import, initiative rolls)
- 2 coordinating hooks extracted from App.tsx (useInitiativeRolls,
  useAutoStatBlock)
- All 9 affected components refactored from prop-based to context-based
- 6 test files updated to use providers or context mocks
- Prop count enforcement script (max 8 per component interface)
- Constitution principle II-A added (context-based state flow)

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

apps/web/src/components/source-manager.tsx

@@ -8,16 +8,12 @@ import {
 } from "react";
 import type { CachedSourceInfo } from "../adapters/bestiary-cache.js";
 import * as bestiaryCache from "../adapters/bestiary-cache.js";
+import { useBestiaryContext } from "../contexts/bestiary-context.js";
 import { Button } from "./ui/button.js";
 import { Input } from "./ui/input.js";
 
-interface SourceManagerProps {
-	onCacheCleared: () => void;
-}
-
-export function SourceManager({
-	onCacheCleared,
-}: Readonly<SourceManagerProps>) {
+export function SourceManager() {
+	const { refreshCache } = useBestiaryContext();
 	const [sources, setSources] = useState<CachedSourceInfo[]>([]);
 	const [filter, setFilter] = useState("");
 	const [optimisticSources, applyOptimistic] = useOptimistic(
@@ -44,14 +40,14 @@ export function SourceManager({
 		applyOptimistic({ type: "remove", sourceCode });
 		await bestiaryCache.clearSource(sourceCode);
 		await loadSources();
-		onCacheCleared();
+		void refreshCache();
 	};
 
 	const handleClearAll = async () => {
 		applyOptimistic({ type: "clear" });
 		await bestiaryCache.clearAll();
 		await loadSources();
-		onCacheCleared();
+		void refreshCache();
 	};
 
 	const filteredSources = useMemo(() => {