feat(anexos): página de galeria de comprovantes e documentos

Adiciona rota `/attachments` com visualização de todos os anexos do
usuário em grade, visualização inline de imagem e PDF, navegação entre
arquivos do mesmo lançamento e download direto.

Inclui também:
- API REST em `/api/attachments` para servir os arquivos
- Actions `fetch-by-id` e `fetch-dialog-options` em transactions
- Item "Anexos" adicionado à navbar
- `formatBytes` extraído para `src/shared/utils/number.ts`
- Migrations de banco atualizadas
- Fix: uploads e remoções de anexo agora funcionam para todos os
  lançamentos, não apenas os pertencentes a séries

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

src/app/(dashboard)/attachments/loading.tsx

@@ -0,0 +1,38 @@
+import { Skeleton } from "@/shared/components/ui/skeleton";
+
+export default function AnexosLoading() {
+	return (
+		<main className="flex flex-col gap-6">
+			<div className="w-full space-y-6">
+				{/* Header */}
+				<Skeleton className="h-10 w-40 rounded-md bg-foreground/10" />
+
+				{/* Month navigation */}
+				<Skeleton className="h-10 w-64 rounded-md bg-foreground/10" />
+
+				{/* Count */}
+				<Skeleton className="h-4 w-20 rounded-md bg-foreground/10" />
+
+				{/* Grid */}
+				<div className="grid grid-cols-2 gap-3 sm:grid-cols-3 lg:grid-cols-4 xl:grid-cols-5">
+					{Array.from({ length: 10 }).map((_, i) => (
+						<div
+							key={i}
+							className="flex flex-col overflow-hidden rounded-lg border"
+						>
+							<Skeleton className="aspect-square w-full bg-foreground/10" />
+							<div className="space-y-1.5 p-2.5">
+								<Skeleton className="h-3 w-3/4 rounded bg-foreground/10" />
+								<Skeleton className="h-3 w-full rounded bg-foreground/10" />
+								<div className="flex justify-between">
+									<Skeleton className="h-3 w-16 rounded bg-foreground/10" />
+									<Skeleton className="h-3 w-12 rounded bg-foreground/10" />
+								</div>
+							</div>
+						</div>
+					))}
+				</div>
+			</div>
+		</main>
+	);
+}

src/app/(dashboard)/attachments/page.tsx

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+import { connection } from "next/server";
+import { AttachmentsPage } from "@/features/attachments/components/attachments-page";
+import { fetchAttachmentsForPeriod } from "@/features/attachments/queries";
+import { getUserId } from "@/shared/lib/auth/server";
+import { parsePeriodParam } from "@/shared/utils/period";
+
+type PageSearchParams = Promise<Record<string, string | string[] | undefined>>;
+
+type PageProps = {
+	searchParams?: PageSearchParams;
+};
+
+const getSingleParam = (
+	params: Record<string, string | string[] | undefined> | undefined,
+	key: string,
+) => {
+	const value = params?.[key];
+	if (!value) return null;
+	return Array.isArray(value) ? (value[0] ?? null) : value;
+};
+
+export default async function Page({ searchParams }: PageProps) {
+	await connection();
+	const userId = await getUserId();
+	const resolvedSearchParams = searchParams ? await searchParams : undefined;
+	const periodoParam = getSingleParam(resolvedSearchParams, "periodo");
+	const { period } = parsePeriodParam(periodoParam);
+
+	const attachments = await fetchAttachmentsForPeriod(userId, period);
+
+	return (
+		<main className="flex flex-col gap-6">
+			<AttachmentsPage attachments={attachments} />
+		</main>
+	);
+}