feat: senior citizen rate fix, joint ownership cap, FD/RD UI improvements

- Senior citizen interest rate correctly sent in FD/RD create payload
  (isSeniorCitizen, seniorCitizenInterestRate, nominalAnnualInterestRate override)
- Joint account ownership capped at 100%: Add Holder/Partner button disabled
  when 100% reached; dialog enforces remaining share as max across all account types
- FD/RD interest rate chart step: rate calculator with tenure, senior citizen toggle,
  maturity preview
- FD/RD preview step improvements
- Base FD interest rate chart component added under fixed-deposit-products
- Base recurring deposit interest rate chart component removed (replaced)
- Savings account details step: joint holder improvements
- Products routing and module updated for base FD rate chart

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

src/app/savings/savings-account-stepper/savings-account-details-step/savings-account-details-step.component.html

@@ -226,6 +226,7 @@
               color="primary"
               type="button"
               class="soa-add-btn"
+              [disabled]="totalJointSharePercentage >= 100"
               (click)="openAddJointHolderDialog()"
             >
               <mat-icon>person_add</mat-icon> Add Holder

src/app/savings/savings-account-stepper/savings-account-details-step/savings-account-details-step.component.ts

@@ -334,11 +334,12 @@ export class SavingsAccountDetailsStepComponent implements OnInit {
       ...(this.primaryClientId ? [this.primaryClientId] : []),
       ...this.jointHolders.map((h: any) => h.clientId).filter(Boolean)
     ];
+    const maxSharePercentage = Math.max(0, 100 - this.totalJointSharePercentage);
     const ref = this.dialog.open(AddRelatedClientDialogComponent, {
       width: '500px',
       panelClass: 'arc-dialog-panel',
       disableClose: true,
-      data: { excludedClientIds }
+      data: { excludedClientIds, maxSharePercentage }
     });
     ref.afterClosed().subscribe((result) => {
       if (result) {