feat(rbi-reserve,savings): Form 1/Form 9 returns UI, branch-wise interest posting reports and summary

- Reports > Interest Posting Reports: per branch and product, generate/regenerate
  at any time, approve; branch column, HO-on-behalf marker, posted txn per account
- Reports > Interest Posting Summary (branch-wise) for the head office, with Excel export
- Day Close warns and disables Close Day while the branch's interest report is unapproved
- Savings product accounting: Interest On Savings (expense), Savings Interest Payable
  and Paid (liability rows, required)
- RBI Form 1 statutory and Form 9 return screens, reserve config updates
- Interest posting report GETs exempted from the response cache

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/app/rbi-circulars/rbi-circulars-routing.module.ts

@@ -69,12 +69,24 @@ const routes: Routes = [
       loadComponent: () => import('./reserve-return/form1-crr.component').then((m) => m.Form1CrrComponent),
       data: { title: 'Form 1 — Cash Reserve Ratio', breadcrumb: 'Form 1 (CRR)' }
     },
+    // Form 9 (SLR) has no route of its own. Section 24 is settled on the statutory Form 1 at Part C,
+    // charged on the same liabilities Part B charges the cash reserve on. A second screen computing
+    // the same ratio from a month-end base disagreed with it, and both were headed Form 9 — whichever
+    // a filer read, they had no way to know the other said something else.
     {
-      // SLR return, filed at the end of each month.
-      path: 'rbi/form9',
-      loadComponent: () => import('./reserve-return/form9-slr.component').then((m) => m.Form9SlrComponent),
-      data: { title: 'Form 9 — Statutory Liquidity Ratio', breadcrumb: 'Form 9 (SLR)' }
+      // Form IX — the Return on Assets and Liabilities, code R408, filed monthly.
+      //
+      // A DIFFERENT return from Form 9 (SLR) above despite the name. That one reports one ratio;
+      // this one reports the whole balance sheet, in rupees thousands, and its two sides must
+      // agree. Its own route rather than a tab on rbi/form9 for exactly that reason — they answer
+      // different questions and share no figures.
+      path: 'rbi/form9-return',
+      loadComponent: () => import('./form9-return/form9-return.component').then((m) => m.Form9ReturnComponent),
+      data: { title: 'Form IX — Return on Assets and Liabilities', breadcrumb: 'Form IX (R408)' }
     }
+    // The statutory Form 1 has no route of its own: it is a tab on rbi/form1. Both are Form 1 for
+    // one bank and one period, and two routes made a filer guess which held which — one could be
+    // read while the other was believed to be on screen.
   ])
 ];