feat(analysis): add monthly variation table with inflation comparison

- New backend endpoint GET /api/quotes/monthly-last
- MonthlyVariationTable component with BELO/Blue/Oficial % changes
- Inflation data from ArgentinaDatos API with 24h cache
- Visual indicators: green if beats inflation, red if below
- Responsive: cards on mobile, table on desktop

apps/backend/src/modules/quotes/handlers/getMonthlyLast.ts

@@ -0,0 +1,28 @@
+import type { Context } from "hono";
+import { cache } from "../../../lib/cache";
+import { prisma } from "../../../lib/prisma";
+
+export async function getMonthlyLast(c: Context) {
+  const cacheKey = "quotes:monthly-last";
+  const cached = cache.get(cacheKey);
+  if (cached) return c.json(cached);
+
+  const rows = await prisma.$queryRaw<
+    Array<{
+      month: string;
+      type: string;
+      buy: number;
+    }>
+  >`
+    SELECT
+      TO_CHAR(DATE_TRUNC('month', "timeStamp"), 'YYYY-MM') AS month,
+      "type"::text,
+      (ARRAY_AGG(buy ORDER BY "timeStamp" DESC))[1]::numeric::float8 AS buy
+    FROM "quotes_history"
+    GROUP BY DATE_TRUNC('month', "timeStamp"), "type"
+    ORDER BY month ASC
+  `;
+
+  cache.set(cacheKey, rows, 300);
+  return c.json(rows);
+}

apps/backend/src/modules/quotes/quotes.routes.ts

@@ -4,12 +4,14 @@ import { getCurrentQuotes } from "./handlers/getCurrentQuotes";
 import { getDailyMinMax } from "./handlers/getDailyMinMax";
 import { getDailyQuotes } from "./handlers/getDailyQuotes";
 import { getHistoricalMinMax } from "./handlers/getHistoricalMinMax";
+import { getMonthlyLast } from "./handlers/getMonthlyLast";
 import { getQuoteHistory } from "./handlers/getQuoteHistory";
 import { quoteEvents } from "./handlers/quoteEvents";
 
 const app = new Hono();
 
 app.get("/", getCurrentQuotes);
+app.get("/monthly-last", getMonthlyLast);
 app.get("/:type/history", getQuoteHistory);
 app.get("/:type/daily", getDailyQuotes);
 app.get("/:type/min-max", getDailyMinMax);