fix(lint): resolve ESLint errors in form dialogs and error boundary

- Replace useEffect setState pattern with initial state from props +
  key-based remount in SiteFormDialog and SectorFormDialog
- Fix explicit-any violation in error boundary context assignment

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/routes/_authenticated/tenants/$tenantId/sites/index.tsx

@@ -39,6 +39,7 @@ function SitesPage() {
       />
       <SiteFormDialog open={createOpen} onOpenChange={setCreateOpen} tenantId={tenantId} />
       <SiteFormDialog
+        key={editSite?.id ?? 'new'}
         open={!!editSite}
         onOpenChange={(open) => {
           if (!open) setEditSite(null)