feat: remove Administration workspace — keep only Verwaltung + Suche

- Delete all ops page components (ReviewQueue, AIMonitoring, Governance,
  SourceMonitoring, ActivityTimeline, SignalPipeline)
- Remove OPERATIONS workspace from AppShell config, nav order, path detection
- Remove all /ops/* routes from App.tsx
- Remove WorkspaceType.OPERATIONS from allowedWorkspaces in authService,
  sessionStore, permissions
- Keep MarketIntelligence page (already moved to /supply/market-intelligence)

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

.claude/worktrees/agent-a82a3716/src/components/ui/PageContainer.tsx

@@ -0,0 +1,19 @@
+import { Box } from '@mui/material'
+import type { ReactNode } from 'react'
+
+interface PageContainerProps {
+  children: ReactNode
+  maxWidth?: string | number
+  className?: string
+}
+
+export function PageContainer({ children, maxWidth = 1440, className = '' }: PageContainerProps) {
+  return (
+    <Box
+      className={`w-full mx-auto px-6 py-6 ${className}`}
+      sx={{ maxWidth }}
+    >
+      {children}
+    </Box>
+  )
+}