feat: Phase 1B complete - Perwerde & ValidatorPool UI

Perwerde (Education Platform):
- Add hybrid backend (Supabase + Blockchain + IPFS)
- Implement CourseList, CourseCreator, StudentDashboard
- Create courses table with RLS policies
- Add IPFS upload utility
- Integrate with pallet-perwerde extrinsics

ValidatorPool:
- Add validator pool management UI
- Implement PoolCategorySelector with 3 categories
- Add ValidatorPoolDashboard with pool stats
- Integrate with pallet-validator-pool extrinsics
- Add to StakingDashboard as new tab

Technical:
- Fix all toast imports (sonner)
- Fix IPFS File upload (Blob conversion)
- Fix RLS policies (wallet_address → auth.uid)
- Add error boundaries
- Add loading states

Status: UI complete, blockchain integration pending VPS deployment

web/src/components/staking/PoolCategorySelector.tsx

@@ -0,0 +1,40 @@
+import React, { useState } from 'react';
+import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select';
+import { Button } from '@/components/ui/button';
+import { Loader2 } from 'lucide-react';
+import { ValidatorPoolCategory } from '@shared/lib/validator-pool';
+
+interface PoolCategorySelectorProps {
+  currentCategory?: ValidatorPoolCategory;
+  onCategoryChange: (category: ValidatorPoolCategory) => void;
+  disabled?: boolean;
+}
+
+const POOL_CATEGORIES = Object.values(ValidatorPoolCategory);
+
+export function PoolCategorySelector({ currentCategory, onCategoryChange, disabled }: PoolCategorySelectorProps) {
+  const [selectedCategory, setSelectedCategory] = useState<ValidatorPoolCategory>(currentCategory || POOL_CATEGORIES[0]);
+
+  const handleSubmit = () => {
+    onCategoryChange(selectedCategory);
+  };
+
+  return (
+    <div className="space-y-4">
+      <Select value={selectedCategory} onValueChange={(value) => setSelectedCategory(value as ValidatorPoolCategory)} disabled={disabled}>
+        <SelectTrigger className="w-full bg-gray-800 border-gray-700 text-white">
+          <SelectValue placeholder="Select a pool category..." />
+        </SelectTrigger>
+        <SelectContent>
+          {POOL_CATEGORIES.map(cat => (
+            <SelectItem key={cat} value={cat}>{cat.replace(/([A-Z])/g, ' $1').trim()}</SelectItem>
+          ))}
+        </SelectContent>
+      </Select>
+      <Button onClick={handleSubmit} disabled={disabled || !selectedCategory} className="w-full">
+        {disabled && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+        {currentCategory ? 'Switch Category' : 'Join Pool'}
+      </Button>
+    </div>
+  );
+}