Add deposit slip and report generation

- New Deposits tab with ledger: date, checks total, cash, deposit total, item count, status
- Slide-in deposit panel: date, currency, coin, cash back, dynamic check entry rows, live totals
- Save deposit, then generate Deposit Slip or Deposit Report PDF
- Deposit slip: 3.375" x 8.5" portrait with Style A background drawn server-side,
  digit-column amounts, GnuMICR routing/account line rotated 90 deg, rotated
  deposit total and check count in left margin
- Deposit report: plain Courier ledger with depositor/bank info, check grid, totals
- deposits and deposit_items tables in schema; ON DELETE CASCADE for items
- Routes: GET/POST/PUT/DELETE /api/deposits, POST /api/deposit-pdf
- Generating a slip marks deposit as printed; date range and status filters
- README updated to describe deposit slip feature

src/app.js

@@ -14,8 +14,10 @@ app.use(express.json());
 app.use(express.static(path.join(__dirname, '../public')));
 
 // Routes
-app.use('/api/checks', require('./routes/checks'));
-app.use('/api/pdf',    require('./routes/pdf'));
+app.use('/api/checks',      require('./routes/checks'));
+app.use('/api/pdf',         require('./routes/pdf'));
+app.use('/api/deposits',    require('./routes/deposits'));
+app.use('/api/deposit-pdf', require('./routes/deposit-pdf'));
 
 // GET /api/accounts - list all accounts (id + display name)
 app.get('/api/accounts', (req, res) => {