fix: cash flow forecast drops investments purchased within the charted window

The Issue 2 fix made the opening investment balance point-in-time
(only CDs purchased before startYear-01-01), with a comment promising
that later purchases would be re-added "when their purchase month is
processed in the forecast loop" — but that loop code never existed.
The loop only ever subtracted maturing CDs, never added purchased ones.

Result: every CD bought during the charted window vanished from the
chart. For Pine Creek (all 5 CDs purchased in 2026) the operating
investment line showed $0 instead of $65,000 and reserve showed
$10,000 instead of $60,032.

Fix: build a purchaseIndex (mirroring maturityIndex) of investments
purchased on/after startYear-01-01, keyed by purchase year-month, and
credit each CD's value to the running investment balance in its
purchase month — applied before the historical/forecast branch so it
works for both actual and projected months.

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

backend/src/modules/reports/reports.service.ts

@@ -1008,6 +1008,19 @@ export class ReportsService {
       WHERE is_active = true AND maturity_date IS NOT NULL AND maturity_date > CURRENT_DATE
     `);
 
+    // ── 5b) Get investment purchases (cash converts to an investment balance in the
+    // month the CD is bought). Only investments purchased on/after startYear-01-01 are
+    // indexed here — anything earlier is already counted in the opening investment
+    // balance below. Without this, point-in-time opening balances would silently drop
+    // every CD bought during the charted window.
+    const purchases = await this.tenant.query(`
+      SELECT fund_type, current_value, purchase_date
+      FROM investment_accounts
+      WHERE is_active = true
+        AND purchase_date IS NOT NULL
+        AND purchase_date >= $1::date
+    `, [`${startYear}-01-01`]);
+
     // ── 6) Get capital project planned expenses ──
     const projectExpenses = await this.tenant.query(`
       SELECT estimated_cost, target_year, target_month, fund_source
@@ -1077,6 +1090,19 @@ export class ReportsService {
       else maturityIndex[key].reserve += maturityTotal;
     }
 
+    // Index investment purchases by year-month — added to the running investment
+    // balance in the month the CD was bought (applies to both historical & forecast
+    // months, since a purchase is a real event regardless of where "now" falls).
+    const purchaseIndex: Record<string, { operating: number; reserve: number }> = {};
+    for (const inv of purchases) {
+      const d = new Date(inv.purchase_date);
+      const key = `${d.getFullYear()}-${d.getMonth() + 1}`;
+      if (!purchaseIndex[key]) purchaseIndex[key] = { operating: 0, reserve: 0 };
+      const val = parseFloat(inv.current_value) || 0;
+      if (inv.fund_type === 'operating') purchaseIndex[key].operating += val;
+      else purchaseIndex[key].reserve += val;
+    }
+
     // Index project expenses by year-month
     const projectIndex: Record<string, { operating: number; reserve: number }> = {};
     for (const p of projectExpenses) {
@@ -1129,6 +1155,12 @@ export class ReportsService {
       const isHistorical = isPastMonth && hasActuals;
       const label = `${monthLabels[month - 1]} ${year}`;
 
+      // Apply investment purchases for this month before branching — a CD bought
+      // this month raises the investment balance whether the month is actual or forecast.
+      const purchased = purchaseIndex[key] || { operating: 0, reserve: 0 };
+      runOpInv += purchased.operating;
+      runResInv += purchased.reserve;
+
       if (isHistorical) {
         // Use actual journal entry changes from asset accounts
         const opChange = histIndex[`${year}-${month}-operating`] || 0;