feat(ST-qfpqpxzy): DB schema + settings-UI voor min_quota_pct worker-drempel (#118)

- User.min_quota_pct Int @default(20) + ClaudeWorker.last_quota_pct/last_quota_check_at
- Migratie add_worker_quota_gate
- lib/schemas/user.ts: minQuotaPctSchema (int, 1-100)
- actions/settings.ts: updateMinQuotaPctAction met auth/demo/zod-guard
- MinQuotaEditor component met numeric input en DemoTooltip
- Settings-pagina: Worker-instellingen sectie

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

components/settings/min-quota-editor.tsx

@@ -0,0 +1,59 @@
+'use client'
+
+import { useState, useTransition } from 'react'
+import { toast } from 'sonner'
+import { Button } from '@/components/ui/button'
+import { DemoTooltip } from '@/components/shared/demo-tooltip'
+import { updateMinQuotaPctAction } from '@/actions/settings'
+
+interface MinQuotaEditorProps {
+  currentValue: number
+  isDemo: boolean
+}
+
+export function MinQuotaEditor({ currentValue, isDemo }: MinQuotaEditorProps) {
+  const [value, setValue] = useState(currentValue)
+  const [isPending, startTransition] = useTransition()
+
+  function handleSave() {
+    startTransition(async () => {
+      const result = await updateMinQuotaPctAction(value)
+      if ('error' in result) {
+        toast.error(result.error as string)
+      } else {
+        toast.success('Instelling opgeslagen')
+      }
+    })
+  }
+
+  return (
+    <div className="space-y-3">
+      <div>
+        <label htmlFor="min-quota-pct" className="text-sm font-medium text-foreground">
+          Minimaal beschikbaar Claude-quota voordat de worker een job oppakt (%)
+        </label>
+        <p className="text-xs text-muted-foreground mt-0.5">
+          Worker slaapt tot quota gereset is wanneer onder deze drempel.
+        </p>
+      </div>
+      <div className="flex items-center gap-3">
+        <input
+          id="min-quota-pct"
+          type="number"
+          min={1}
+          max={100}
+          value={value}
+          onChange={e => setValue(Number(e.target.value))}
+          disabled={isDemo || isPending}
+          className="w-24 rounded border border-border bg-surface-container px-3 py-1.5 text-sm text-foreground focus:outline-none focus:ring-1 focus:ring-primary disabled:opacity-50"
+        />
+        <span className="text-sm text-muted-foreground">%</span>
+        <DemoTooltip show={isDemo}>
+          <Button onClick={handleSave} disabled={isDemo || isPending} size="sm">
+            Opslaan
+          </Button>
+        </DemoTooltip>
+      </div>
+    </div>
+  )
+}