Float management: save→view/print, history columns, uploads path fix

- Change tin count: remove bags/loose split — single qty per denomination
- After save: show saved record inline with Print button (clean new-window
  printout with denomination table, receipts, totals/variance, signature lines)
- Change tin print: bank exchange order table (surplus=to bank, shortfall=in exchange)
- Petty cash history: Cash | Receipts | Total | Variance columns
- Fix uploads path: /app/src/../../uploads resolved to /uploads (container root,
  outside Docker volume). Changed to /app/src/../uploads = /app/uploads so files
  persist across rebuilds on the named volume.

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

backend/src/index.js

@@ -13,7 +13,7 @@ import { floatRoutes } from './routes/floats.js'
 import { settingsRoutes } from './routes/settings.js'
 
 const __dirname = dirname(fileURLToPath(import.meta.url))
-const UPLOADS_DIR = join(__dirname, '..', '..', 'uploads')
+const UPLOADS_DIR = join(__dirname, '..', 'uploads')
 
 const app = Fastify({ logger: true, trustProxy: true })