Implement fiscal-style research MVP flows

app/financials/page.tsx

@@ -178,6 +178,50 @@ function mergeSurfaceRows<T extends { key: string; values: Record<string, number
   return [...rowMap.values()];
 }
 
+function mergeOverviewMetrics(
+  base: CompanyFinancialStatementsResponse['overviewMetrics'],
+  next: CompanyFinancialStatementsResponse['overviewMetrics']
+): CompanyFinancialStatementsResponse['overviewMetrics'] {
+  const mergedSeriesMap = new Map<string, CompanyFinancialStatementsResponse['overviewMetrics']['series'][number]>();
+
+  for (const source of [base.series, next.series]) {
+    for (const point of source) {
+      const existing = mergedSeriesMap.get(point.periodId);
+      if (!existing) {
+        mergedSeriesMap.set(point.periodId, { ...point });
+        continue;
+      }
+
+      existing.filingDate = existing.filingDate || point.filingDate;
+      existing.periodEnd = existing.periodEnd ?? point.periodEnd;
+      existing.label = existing.label || point.label;
+      existing.revenue = existing.revenue ?? point.revenue;
+      existing.netIncome = existing.netIncome ?? point.netIncome;
+      existing.totalAssets = existing.totalAssets ?? point.totalAssets;
+      existing.cash = existing.cash ?? point.cash;
+      existing.debt = existing.debt ?? point.debt;
+    }
+  }
+
+  const series = [...mergedSeriesMap.values()].sort((left, right) => {
+    return Date.parse(left.periodEnd ?? left.filingDate) - Date.parse(right.periodEnd ?? right.filingDate);
+  });
+  const latest = series[series.length - 1] ?? null;
+
+  return {
+    referencePeriodId: next.referencePeriodId ?? base.referencePeriodId ?? latest?.periodId ?? null,
+    referenceDate: next.referenceDate ?? base.referenceDate ?? latest?.filingDate ?? null,
+    latest: {
+      revenue: next.latest.revenue ?? base.latest.revenue ?? latest?.revenue ?? null,
+      netIncome: next.latest.netIncome ?? base.latest.netIncome ?? latest?.netIncome ?? null,
+      totalAssets: next.latest.totalAssets ?? base.latest.totalAssets ?? latest?.totalAssets ?? null,
+      cash: next.latest.cash ?? base.latest.cash ?? latest?.cash ?? null,
+      debt: next.latest.debt ?? base.latest.debt ?? latest?.debt ?? null
+    },
+    series
+  };
+}
+
 function mergeFinancialPages(
   base: CompanyFinancialStatementsResponse | null,
   next: CompanyFinancialStatementsResponse
@@ -317,6 +361,7 @@ function mergeFinancialPages(
       ...next.dataSourceStatus,
       queuedSync: base.dataSourceStatus.queuedSync || next.dataSourceStatus.queuedSync
     },
+    overviewMetrics: mergeOverviewMetrics(base.overviewMetrics, next.overviewMetrics),
     dimensionBreakdown
   };
 }
@@ -342,6 +387,33 @@ function buildOverviewSeries(
   incomeData: CompanyFinancialStatementsResponse | null,
   balanceData: CompanyFinancialStatementsResponse | null
 ): OverviewPoint[] {
+  const overviewSeriesMap = new Map<string, OverviewPoint>();
+
+  for (const source of [incomeData?.overviewMetrics.series ?? [], balanceData?.overviewMetrics.series ?? []]) {
+    for (const point of source) {
+      const existing = overviewSeriesMap.get(point.periodId);
+      if (!existing) {
+        overviewSeriesMap.set(point.periodId, { ...point });
+        continue;
+      }
+
+      existing.filingDate = existing.filingDate || point.filingDate;
+      existing.periodEnd = existing.periodEnd ?? point.periodEnd;
+      existing.label = existing.label || point.label;
+      existing.revenue = existing.revenue ?? point.revenue;
+      existing.netIncome = existing.netIncome ?? point.netIncome;
+      existing.totalAssets = existing.totalAssets ?? point.totalAssets;
+      existing.cash = existing.cash ?? point.cash;
+      existing.debt = existing.debt ?? point.debt;
+    }
+  }
+
+  if (overviewSeriesMap.size > 0) {
+    return [...overviewSeriesMap.values()].sort((left, right) => {
+      return Date.parse(left.periodEnd ?? left.filingDate) - Date.parse(right.periodEnd ?? right.filingDate);
+    });
+  }
+
   const periodMap = new Map<string, { filingDate: string; periodEnd: string | null }>();
 
   for (const source of [incomeData, balanceData]) {
@@ -609,27 +681,36 @@ function FinancialsPageContent() {
 
   const latestStandardizedIncome = overviewIncome?.surfaces.standardized.rows ?? [];
   const latestStandardizedBalance = overviewBalance?.surfaces.standardized.rows ?? [];
-  const latestRevenue = latestOverview?.revenue
+  const latestRevenue = overviewIncome?.overviewMetrics.latest.revenue
+    ?? latestOverview?.revenue
     ?? findStandardizedRow(latestStandardizedIncome, 'revenue')?.values[periods[periods.length - 1]?.id ?? '']
     ?? latestTaxonomyMetrics?.revenue
     ?? null;
-  const latestNetIncome = latestOverview?.netIncome
+  const latestNetIncome = overviewIncome?.overviewMetrics.latest.netIncome
+    ?? latestOverview?.netIncome
     ?? findStandardizedRow(latestStandardizedIncome, 'net-income')?.values[periods[periods.length - 1]?.id ?? '']
     ?? latestTaxonomyMetrics?.netIncome
     ?? null;
-  const latestTotalAssets = latestOverview?.totalAssets
+  const latestTotalAssets = overviewBalance?.overviewMetrics.latest.totalAssets
+    ?? latestOverview?.totalAssets
     ?? findStandardizedRow(latestStandardizedBalance, 'total-assets')?.values[periods[periods.length - 1]?.id ?? '']
     ?? latestTaxonomyMetrics?.totalAssets
     ?? null;
-  const latestCash = latestOverview?.cash
+  const latestCash = overviewBalance?.overviewMetrics.latest.cash
+    ?? latestOverview?.cash
     ?? findStandardizedRow(latestStandardizedBalance, 'cash-and-equivalents')?.values[periods[periods.length - 1]?.id ?? '']
     ?? latestTaxonomyMetrics?.cash
     ?? null;
-  const latestDebt = latestOverview?.debt
+  const latestDebt = overviewBalance?.overviewMetrics.latest.debt
+    ?? latestOverview?.debt
     ?? findStandardizedRow(latestStandardizedBalance, 'total-debt')?.values[periods[periods.length - 1]?.id ?? '']
     ?? latestTaxonomyMetrics?.debt
     ?? null;
-  const latestReferenceDate = latestOverview?.filingDate ?? periods[periods.length - 1]?.filingDate ?? null;
+  const latestReferenceDate = overviewIncome?.overviewMetrics.referenceDate
+    ?? overviewBalance?.overviewMetrics.referenceDate
+    ?? latestOverview?.filingDate
+    ?? periods[periods.length - 1]?.filingDate
+    ?? null;
 
   const selectedRow = useMemo(() => {
     if (!selectedRowKey) {