Title: refactor(client, contract): migrate tables and forms from MUI to ShadCN unified design

Description:

Summary

• Migrate client table section from MUI (TableManager, Box, Stack,
  Checkbox, SvgColor, ConditionalComponent) to the ShadCN unified CSS grid table design
• Migrate contract table, list view, circuits table, and form from MUI to
  ShadCN/Tailwind with Lucide icons
• Add new client-table.tsx, client-table-row.tsx, and contract-table-row.tsx
  components following the canonical grid table pattern from circuit module

Changes

Client (new)

• client-table.tsx — CSS grid table with buildGridTemplate, synced horizontal scroll, loading skeletons, empty state, scroll gradient overlays, backend pagination via onPageChange/onRowsPerPageChange
• client-table-row.tsx — Animated row (IntersectionObserver), color accent bar from colorCode, ShadCN Checkbox/TableActionColumn, cell rendering (dates,
  portalAssignment, mainBranch, typeClient mappings), inactive opacity styling, toggle activation with ConfirmDialog
• client-list-view.tsx — Replace MUI components with ShadCN TableControlBar, TabsCustom, TabContentContainer/TabPanel, Lucide Upload; fix navigation
  type mismatch (String(c.id) === id)

Contract (refactored)

• contract-table.tsx — Replace MUI TableManager with CSS grid table layout, add row selection, scroll sync
• contract-table-row.tsx — New animated grid row with color accent, ShadCN
  actions, ConfirmDialog
• contrat-circuits-table.tsx — Replace MUI Table/TableBody/TableCell/CircularProgress/SvgColor with Tailwind grid,
  Lucide icons, animated rows
• contract-list-view.tsx — Replace MUI layout/tabs/dialog with ShadCN equivalents, Lucide Upload
• contract-new-view.tsx — Replace MUI form components (Radio, Grid, Box,
  FormHelperText) with Tailwind/Lucide, ShadCN form-field/form-container, add
  Section card wrapper

Closes VSN-2342