fix(reports): thread accountIds into Cartes KPI + seasonality series

getCartesSnapshot forwarded the account filter only to the top-movers and
budget sub-reports, leaving fetchMonthlyFlows (KPIs, sparklines, 12-month
overlay) and fetchSeasonality unfiltered. The Dashboard is the first page to
expose the account filter over these series, so its KPI cards showed
unfiltered totals while the category bars / trend / top-movers respected the
filter — figures that did not reconcile on the same screen.

Thread an optional accountIds through both fetchers (parameterized
`source_id IN (...)` via inPlaceholders) and pass it from getCartesSnapshot,
so the whole dashboard honours the filter — which is what the #279 CHANGELOG
entry already promises. No CHANGELOG change: the code now matches the note.

Resolves #279

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/services/reportService.cartes.test.ts

@@ -470,13 +470,14 @@ describe("getCartesSnapshot", () => {
     expect(worst.overrunPct).toBeCloseTo(75, 5);
   });
 
-  // --- accountIds filter (Issue #273) ---
+  // --- accountIds filter (Issues #273 / #279) ---
   //
-  // getCartesSnapshot must forward accountIds to its two sub-reports that
+  // getCartesSnapshot must forward accountIds to EVERY sub-query so the whole
+  // dashboard honours an active account filter: the two sub-reports that
   // support it (getCompareMonthOverMonth for top movers, getBudgetVsActualData
-  // for budget adherence) — the review caveat that flagged this: omitting it
-  // would let this dashboard silently ignore an active account filter even
-  // though its own building blocks respect it.
+  // for budget adherence) AND the KPI/sparkline/seasonality series
+  // (fetchMonthlyFlows, fetchSeasonality). Omitting it anywhere would let the
+  // dashboard silently mix filtered and unfiltered figures on the same screen.
 
   it("forwards accountIds to the compare (top movers) sub-report", async () => {
     mockSelect.mockImplementation(() => Promise.resolve([]));
@@ -506,6 +507,32 @@ describe("getCartesSnapshot", () => {
     }
   });
 
+  it("forwards accountIds to the monthly-flows series (KPIs, sparklines, overlay)", async () => {
+    mockSelect.mockImplementation(() => Promise.resolve([]));
+
+    await getCartesSnapshot(2026, 3, "month", [3, 8]);
+
+    // fetchMonthlyFlows is the only snapshot query selecting a "%Y-%m" month.
+    const flowCall = mockSelect.mock.calls.find(([sql]) =>
+      (sql as string).includes("strftime('%Y-%m', date) AS month"),
+    )!;
+    expect(flowCall[0]).toContain("AND source_id IN ($3, $4)");
+    expect(flowCall[1]).toEqual(expect.arrayContaining([3, 8]));
+  });
+
+  it("forwards accountIds to the seasonality series", async () => {
+    mockSelect.mockImplementation(() => Promise.resolve([]));
+
+    await getCartesSnapshot(2026, 3, "month", [3, 8]);
+
+    // fetchSeasonality is the only snapshot query filtering on a "%m" month.
+    const seasonalityCall = mockSelect.mock.calls.find(([sql]) =>
+      (sql as string).includes("strftime('%m', date) = $1"),
+    )!;
+    expect(seasonalityCall[0]).toContain("AND source_id IN ($4, $5)");
+    expect(seasonalityCall[1]).toEqual(expect.arrayContaining([3, 8]));
+  });
+
   it("without accountIds, no sub-report SQL carries a source_id clause (regression)", async () => {
     mockSelect.mockImplementation(() => Promise.resolve([]));
 

src/services/reportService.ts

@@ -1186,18 +1186,25 @@ interface RawMonthFlow {
 async function fetchMonthlyFlows(
   dateFrom: string,
   dateTo: string,
+  accountIds?: number[],
 ): Promise<RawMonthFlow[]> {
   const db = await getDb();
+  const params: unknown[] = [dateFrom, dateTo];
+  const accountPlaceholders = inPlaceholders(accountIds, 3);
+  const accountClause = accountPlaceholders
+    ? ` AND source_id IN (${accountPlaceholders})`
+    : "";
+  if (accountPlaceholders) params.push(...accountIds!);
   return db.select<RawMonthFlow[]>(
     `SELECT
         strftime('%Y-%m', date) AS month,
         COALESCE(SUM(CASE WHEN amount > 0 THEN amount ELSE 0 END), 0) AS income,
         ABS(COALESCE(SUM(CASE WHEN amount < 0 THEN amount ELSE 0 END), 0)) AS expenses
       FROM transactions
-      WHERE date >= $1 AND date <= $2
+      WHERE date >= $1 AND date <= $2${accountClause}
       GROUP BY month
       ORDER BY month ASC`,
-    [dateFrom, dateTo],
+    params,
   );
 }
 
@@ -1210,9 +1217,16 @@ async function fetchSeasonality(
   month: number,
   yearFrom: number,
   yearTo: number,
+  accountIds?: number[],
 ): Promise<RawSeasonalityRow[]> {
   const db = await getDb();
   const mm = String(month).padStart(2, "0");
+  const params: unknown[] = [mm, yearFrom, yearTo];
+  const accountPlaceholders = inPlaceholders(accountIds, 4);
+  const accountClause = accountPlaceholders
+    ? ` AND source_id IN (${accountPlaceholders})`
+    : "";
+  if (accountPlaceholders) params.push(...accountIds!);
   return db.select<RawSeasonalityRow[]>(
     `SELECT
         CAST(strftime('%Y', date) AS INTEGER) AS year,
@@ -1220,10 +1234,10 @@ async function fetchSeasonality(
       FROM transactions
       WHERE strftime('%m', date) = $1
         AND CAST(strftime('%Y', date) AS INTEGER) >= $2
-        AND CAST(strftime('%Y', date) AS INTEGER) <= $3
+        AND CAST(strftime('%Y', date) AS INTEGER) <= $3${accountClause}
       GROUP BY year
       ORDER BY year DESC`,
-    [mm, yearFrom, yearTo],
+    params,
   );
 }
 
@@ -1240,12 +1254,12 @@ async function fetchSeasonality(
  *   4. Budget vs actual for the reference month.
  *   5. Seasonality: same calendar month across the two prior years.
  *
- * `accountIds` (Issue #273) is forwarded to the two sub-reports that already
- * support it (`getCompareMonthOverMonth` for top movers, `getBudgetVsActualData`
- * for budget adherence) — omitting it here would let this dashboard silently
- * ignore an active account filter even though its building blocks respect it.
- * The KPI/sparkline/seasonality series (`fetchMonthlyFlows`, `fetchSeasonality`)
- * do not take an account filter yet; that is out of scope for this issue.
+ * `accountIds` (Issues #273/#279) is forwarded to every sub-query so the whole
+ * dashboard honours an active account filter: the top-movers
+ * (`getCompareMonthOverMonth`) and budget (`getBudgetVsActualData`) sub-reports,
+ * and the KPI/sparkline/seasonality series (`fetchMonthlyFlows`,
+ * `fetchSeasonality`). Omitting it anywhere would let the dashboard silently mix
+ * filtered and unfiltered figures on the same screen.
  */
 export async function getCartesSnapshot(
   referenceYear: number,
@@ -1261,8 +1275,8 @@ export async function getCartesSnapshot(
 
   // Seasonality range: previous 2 years for the same calendar month.
   const [seasonalityRows, flowRows, momRows, budgetRows] = await Promise.all([
-    fetchSeasonality(referenceMonth, referenceYear - 2, referenceYear - 1),
-    fetchMonthlyFlows(windowStartIso, refEnd),
+    fetchSeasonality(referenceMonth, referenceYear - 2, referenceYear - 1, accountIds),
+    fetchMonthlyFlows(windowStartIso, refEnd, accountIds),
     getCompareMonthOverMonth(referenceYear, referenceMonth, accountIds),
     getBudgetVsActualData(referenceYear, referenceMonth, accountIds),
   ]);