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

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

apps/web/src/contexts/bulk-import-context.tsx

@@ -0,0 +1,21 @@
+import { createContext, type ReactNode, useContext } from "react";
+import { useBulkImport } from "../hooks/use-bulk-import.js";
+
+type BulkImportContextValue = ReturnType<typeof useBulkImport>;
+
+const BulkImportContext = createContext<BulkImportContextValue | null>(null);
+
+export function BulkImportProvider({ children }: { children: ReactNode }) {
+	const value = useBulkImport();
+	return (
+		<BulkImportContext.Provider value={value}>
+			{children}
+		</BulkImportContext.Provider>
+	);
+}
+
+export function useBulkImportContext(): BulkImportContextValue {
+	const ctx = useContext(BulkImportContext);
+	if (!ctx) throw new Error("useBulkImportContext requires BulkImportProvider");
+	return ctx;
+}