Fix TypeScript compile errors blocking Docker build

- Add vite-env.d.ts for import.meta.env type support
- Remove unused imports: ChevronRight, useCallback (x2), today
- Silence unused attachments state read (keep setter for future use)
- Fix FloatManagement changeTinTargets reducer: drop unused k, fix v type

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

frontend/src/components/Layout.tsx

@@ -1,6 +1,6 @@
 import { NavLink, useNavigate } from 'react-router-dom'
 import {
-  Banknote, ClipboardList, BarChart2, Wallet, FileText, Settings, LogOut, ChevronRight,
+  Banknote, ClipboardList, BarChart2, Wallet, FileText, Settings, LogOut,
 } from 'lucide-react'
 import type { User } from '../types'