feat(investment,reconciliation): add Export to Excel across Investment, fix export popup

Adds a shared Export to Excel utility (investment-export.ts) and wires it
into every listing/report screen in the Investment module — Dashboard
(break-up + allocation), Reports (all ~20 report shapes), Interest (per
active tab), the FD/Bond/Share Holdings registers, and Masters (per active
master tab). Entry/transaction forms intentionally have no export button.
No sign-off is included here, matching the request to keep that feature
reconciliation-only.

Also fixes the Reconciliation export flow: the Prepared/Checked/Approved
sign-off is now an optional one-off popup shown when "Export to Excel" is
clicked (fields are blank by default and downloading works whether or not
they're filled), replacing the earlier always-visible sign-off card. Also
fixes three reconciliation reports (Sundry Dr/Cr, NEFT/RTGS, UDIR) whose
labels contain "/" — an Excel-forbidden worksheet-name character — which
was silently aborting their export.

src/app/investment/fd-investment/fd-investment.component.ts

@@ -26,6 +26,7 @@ import {
   addPeriod,
   todayDDMMYYYY
 } from '../investment-data';
+import { exportWorkbook } from '../investment-export';
 
 type FdTab = 'holdings' | 'purchase' | 'interest' | 'sell' | 'writeoff' | 'partpayment';
 
@@ -103,6 +104,7 @@ export class FdInvestmentComponent {
     'BRANCH 2'
   ];
 
+  generating = false;
   toastMsg = '';
   toastVisible = false;
   private toastTimer: ReturnType<typeof setTimeout> | undefined;
@@ -450,6 +452,68 @@ export class FdInvestmentComponent {
     return `inv-badge inv-badge--${h.status.toLowerCase()}`;
   }
 
+  // -------------------- Export to Excel (Holdings register) --------------------
+  async exportExcel(): Promise<void> {
+    this.generating = true;
+    try {
+      await exportWorkbook(
+        [
+          {
+            sheetName: 'FD Holdings',
+            title: 'FD Holdings Register',
+            subtitle: `As on ${this.asOnDate}`,
+            headers: [
+              'Cert No',
+              'Party',
+              'Type',
+              'Face Value',
+              'Rate',
+              'Frequency',
+              'Purchase Date',
+              'Maturity Date',
+              'Accrued Interest',
+              'Maturity Value',
+              'Status'
+            ],
+            widths: [
+              14,
+              28,
+              18,
+              16,
+              10,
+              14,
+              14,
+              14,
+              16,
+              16,
+              12
+            ],
+            rows: this.holdings.map((h) => [
+              h.certNo,
+              h.party,
+              h.interestFreq === 'CUMULATIVE' ? 'Cumulative' : 'Payout',
+              h.faceValue,
+              h.interestRate,
+              h.interestFreq,
+              h.purchaseDate,
+              h.maturityDate,
+              this.accrued(h),
+              this.maturity(h),
+              h.status
+            ])
+          }
+        ],
+        `FD-Holdings-${this.asOnDate}`
+      );
+      this.toast('FD Holdings exported.');
+    } catch (err) {
+      console.error('FD Holdings export failed', err);
+      this.toast('Could not generate the workbook — please retry.');
+    } finally {
+      this.generating = false;
+    }
+  }
+
   private toast(msg: string): void {
     this.toastMsg = msg;
     this.toastVisible = true;