feat: add PEZ presale system with wUSDT contribution

Implemented complete presale system for PEZ token distribution:

Backend (Pallet):
- Created pallet-presale at /home/mamostehp/Pezkuwi-SDK/pezkuwi/pallets/presale/
- Accepts wUSDT (Asset ID 2) contributions
- Tracks all contributors and amounts
- Distributes PEZ (Asset ID 1) after 45-day period
- Conversion rate: 1 wUSDT = 100 PEZ
- Includes emergency pause/unpause functionality
- Runtime integration documentation provided

Frontend:
- Created Presale page with contribution form
- Live stats: time remaining, total raised, contributors count
- Real-time balance display and conversion calculator
- Progress bar showing fundraising goal ($1M target)
- Added route /presale and navigation under Trading menu
- Connected to PolkadotContext and WalletContext

Technical Details:
- wUSDT: 6 decimals (Asset ID 2)
- PEZ: 12 decimals (Asset ID 1)
- Duration: 648,000 blocks (45 days @ 6s blocks)
- Treasury: PalletId "py/prsal"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

web/src/App.tsx

@@ -37,6 +37,7 @@ const Elections = lazy(() => import('./pages/Elections'));
 const EducationPlatform = lazy(() => import('./pages/EducationPlatform'));
 const P2PPlatform = lazy(() => import('./pages/P2PPlatform'));
 const DEXDashboard = lazy(() => import('./components/dex/DEXDashboard').then(m => ({ default: m.DEXDashboard })));
+const Presale = lazy(() => import('./pages/Presale'));
 const NotFound = lazy(() => import('@/pages/NotFound'));
 
 // Loading component
@@ -137,6 +138,7 @@ function App() {
                                   <DEXDashboard />
                                 </ProtectedRoute>
                               } />
+                              <Route path="/presale" element={<Presale />} />
                               <Route path="*" element={<NotFound />} />
                             </Routes>
                           </Suspense>

web/src/components/AppLayout.tsx

@@ -19,7 +19,7 @@ import { TreasuryOverview } from './treasury/TreasuryOverview';
 import { FundingProposal } from './treasury/FundingProposal';
 import { SpendingHistory } from './treasury/SpendingHistory';
 import { MultiSigApproval } from './treasury/MultiSigApproval';
-import { ExternalLink, Award, FileEdit, Users2, MessageSquare, ShieldCheck, Wifi, WifiOff, Wallet, DollarSign, PiggyBank, History, Key, TrendingUp, ArrowRightLeft, Lock, LogIn, LayoutDashboard, Settings, Users, Droplet, Mail } from 'lucide-react';
+import { ExternalLink, Award, FileEdit, Users2, MessageSquare, ShieldCheck, Wifi, WifiOff, Wallet, DollarSign, PiggyBank, History, Key, TrendingUp, ArrowRightLeft, Lock, LogIn, LayoutDashboard, Settings, Users, Droplet, Mail, Coins } from 'lucide-react';
 import GovernanceInterface from './GovernanceInterface';
 import RewardDistribution from './RewardDistribution';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
@@ -192,6 +192,13 @@ const AppLayout: React.FC = () => {
                         <Users className="w-4 h-4" />
                         P2P
                       </button>
+                      <button
+                        onClick={() => navigate('/presale')}
+                        className="w-full text-left px-4 py-2 text-gray-300 hover:bg-gray-800 hover:text-white flex items-center gap-2"
+                      >
+                        <Coins className="w-4 h-4" />
+                        Presale
+                      </button>
                       <button
                         onClick={() => setShowStaking(true)}
                         className="w-full text-left px-4 py-2 text-gray-300 hover:bg-gray-800 hover:text-white flex items-center gap-2"

web/src/pages/Presale.tsx

@@ -0,0 +1,372 @@
+import { useState, useEffect } from 'react';
+import { useTranslation } from 'react-i18next';
+import { usePolkadot } from '@/contexts/PolkadotContext';
+import { useWallet } from '@/contexts/WalletContext';
+import { Button } from '@/components/ui/button';
+import { Input } from '@/components/ui/input';
+import { Card } from '@/components/ui/card';
+import { Progress } from '@/components/ui/progress';
+import { Alert, AlertDescription } from '@/components/ui/alert';
+import { Loader2, AlertCircle, CheckCircle2, Timer, TrendingUp, Users } from 'lucide-react';
+import { toast } from 'sonner';
+
+export default function Presale() {
+  const { t } = useTranslation();
+  const { api, selectedAccount, isApiReady } = usePolkadot();
+  const { balances } = useWallet();
+
+  const [wusdtAmount, setWusdtAmount] = useState('');
+  const [timeRemaining, setTimeRemaining] = useState(0);
+  const [totalRaised, setTotalRaised] = useState('0');
+  const [myContribution, setMyContribution] = useState('0');
+  const [active, setActive] = useState(false);
+  const [paused, setPaused] = useState(false);
+  const [loading, setLoading] = useState(false);
+  const [contributorsCount, setContributorsCount] = useState(0);
+
+  useEffect(() => {
+    if (isApiReady) {
+      loadPresaleData();
+      const interval = setInterval(loadPresaleData, 10000);
+      return () => clearInterval(interval);
+    }
+  }, [api, selectedAccount, isApiReady]);
+
+  const loadPresaleData = async () => {
+    if (!api) return;
+
+    try {
+      // Check if presale active
+      const isActive = await api.query.presale.presaleActive();
+      setActive(isActive.toHuman() as boolean);
+
+      // Check if paused
+      const isPaused = await api.query.presale.paused();
+      setPaused(isPaused.toHuman() as boolean);
+
+      if (!isActive.toHuman()) return;
+
+      // Get start block and calculate time remaining
+      const startBlock = await api.query.presale.presaleStartBlock();
+      const currentBlock = await api.query.system.number();
+
+      if (startBlock.isSome) {
+        const start = startBlock.unwrap().toNumber();
+        const current = currentBlock.toNumber();
+        const duration = 45 * 24 * 60 * 10; // 45 days in blocks (6s blocks)
+        const end = start + duration;
+        const remaining = Math.max(0, end - current);
+        setTimeRemaining(remaining * 6); // blocks to seconds
+      }
+
+      // Get total raised
+      const raised = await api.query.presale.totalRaised();
+      const raisedValue = raised.toString();
+      setTotalRaised((parseInt(raisedValue) / 1_000_000).toFixed(2)); // 6 decimals to USDT
+
+      // Get contributors count
+      const contributors = await api.query.presale.contributors();
+      const contributorsList = contributors.toHuman() as string[];
+      setContributorsCount(contributorsList?.length || 0);
+
+      // Get my contribution if wallet connected
+      if (selectedAccount) {
+        const contribution = await api.query.presale.contributions(selectedAccount.address);
+        const contributionValue = contribution.toString();
+        setMyContribution((parseInt(contributionValue) / 1_000_000).toFixed(2));
+      }
+    } catch (error) {
+      if (import.meta.env.DEV) console.error('Error loading presale data:', error);
+    }
+  };
+
+  const handleContribute = async () => {
+    if (!api || !selectedAccount) {
+      toast.error('Please connect your wallet first');
+      return;
+    }
+
+    if (!wusdtAmount || parseFloat(wusdtAmount) <= 0) {
+      toast.error('Please enter a valid amount');
+      return;
+    }
+
+    const amount = parseFloat(wusdtAmount);
+    const wusdtBalance = parseFloat(balances.USDT);
+
+    if (amount > wusdtBalance) {
+      toast.error(`Insufficient wUSDT balance. You have ${wusdtBalance} wUSDT`);
+      return;
+    }
+
+    setLoading(true);
+
+    try {
+      const amountWithDecimals = Math.floor(amount * 1_000_000); // 6 decimals
+
+      const tx = api.tx.presale.contribute(amountWithDecimals);
+
+      await tx.signAndSend(selectedAccount.address, ({ status, events }) => {
+        if (status.isInBlock) {
+          if (import.meta.env.DEV) {
+            console.log(`Transaction included in block: ${status.asInBlock}`);
+          }
+
+          // Check for errors
+          events.forEach(({ event }) => {
+            if (api.events.system.ExtrinsicFailed.is(event)) {
+              const [dispatchError] = event.data;
+              let errorMsg = 'Transaction failed';
+
+              if (dispatchError.isModule) {
+                const decoded = api.registry.findMetaError(dispatchError.asModule);
+                errorMsg = `${decoded.section}.${decoded.name}: ${decoded.docs}`;
+              }
+
+              toast.error(errorMsg);
+              setLoading(false);
+            } else if (api.events.presale?.Contributed?.is(event)) {
+              toast.success(`Successfully contributed ${amount} wUSDT!`);
+              setWusdtAmount('');
+              loadPresaleData();
+              setLoading(false);
+            }
+          });
+        }
+      });
+    } catch (error) {
+      if (import.meta.env.DEV) console.error('Contribution error:', error);
+      toast.error('Contribution failed. Please try again.');
+      setLoading(false);
+    }
+  };
+
+  const formatTime = (seconds: number): string => {
+    const days = Math.floor(seconds / 86400);
+    const hours = Math.floor((seconds % 86400) / 3600);
+    const minutes = Math.floor((seconds % 3600) / 60);
+    return `${days}d ${hours}h ${minutes}m`;
+  };
+
+  const calculatePezReceived = (wusdtAmount: string): number => {
+    const amount = parseFloat(wusdtAmount);
+    return isNaN(amount) ? 0 : amount * 100; // 1 wUSDT = 100 PEZ
+  };
+
+  const progressPercentage = () => {
+    const target = 1_000_000; // Target: $1M
+    const current = parseFloat(totalRaised);
+    return Math.min(100, (current / target) * 100);
+  };
+
+  if (!active) {
+    return (
+      <div className="container mx-auto py-12 px-4">
+        <Card className="p-8 text-center max-w-2xl mx-auto">
+          <div className="mb-6">
+            <div className="w-20 h-20 bg-green-500/20 rounded-full flex items-center justify-center mx-auto mb-4">
+              <Timer className="w-10 h-10 text-green-500" />
+            </div>
+            <h1 className="text-3xl font-bold mb-4">PEZ Token Pre-Sale</h1>
+            <p className="text-muted-foreground">
+              {t('presale.notStarted', 'The pre-sale has not started yet. Please check back soon!')}
+            </p>
+          </div>
+
+          <div className="p-6 bg-muted rounded-lg mt-6">
+            <h3 className="font-semibold mb-3">Pre-Sale Details</h3>
+            <div className="space-y-2 text-sm text-left">
+              <div className="flex justify-between">
+                <span className="text-muted-foreground">Duration:</span>
+                <span className="font-medium">45 Days</span>
+              </div>
+              <div className="flex justify-between">
+                <span className="text-muted-foreground">Conversion Rate:</span>
+                <span className="font-medium">1 wUSDT = 100 PEZ</span>
+              </div>
+              <div className="flex justify-between">
+                <span className="text-muted-foreground">Accepted Token:</span>
+                <span className="font-medium">wUSDT</span>
+              </div>
+            </div>
+          </div>
+        </Card>
+      </div>
+    );
+  }
+
+  return (
+    <div className="container mx-auto py-12 px-4">
+      <div className="max-w-6xl mx-auto">
+        <div className="text-center mb-8">
+          <h1 className="text-4xl font-bold mb-2 bg-gradient-to-r from-green-500 via-yellow-400 to-red-500 bg-clip-text text-transparent">
+            PEZ Token Pre-Sale
+          </h1>
+          <p className="text-muted-foreground">
+            Contribute wUSDT and receive PEZ tokens at a special rate
+          </p>
+        </div>
+
+        {paused && (
+          <Alert className="mb-6 border-yellow-500/50 bg-yellow-500/10">
+            <AlertCircle className="h-4 w-4 text-yellow-500" />
+            <AlertDescription className="text-yellow-600 dark:text-yellow-400">
+              Pre-sale is temporarily paused. Contributions are disabled.
+            </AlertDescription>
+          </Alert>
+        )}
+
+        {/* Stats Grid */}
+        <div className="grid md:grid-cols-4 gap-4 mb-8">
+          <Card className="p-6">
+            <div className="flex items-center justify-between mb-2">
+              <h3 className="text-sm text-muted-foreground">Time Remaining</h3>
+              <Timer className="h-4 w-4 text-green-500" />
+            </div>
+            <p className="text-2xl font-bold text-green-400">{formatTime(timeRemaining)}</p>
+          </Card>
+
+          <Card className="p-6">
+            <div className="flex items-center justify-between mb-2">
+              <h3 className="text-sm text-muted-foreground">Total Raised</h3>
+              <TrendingUp className="h-4 w-4 text-yellow-500" />
+            </div>
+            <p className="text-2xl font-bold text-yellow-400">${totalRaised}</p>
+          </Card>
+
+          <Card className="p-6">
+            <div className="flex items-center justify-between mb-2">
+              <h3 className="text-sm text-muted-foreground">Contributors</h3>
+              <Users className="h-4 w-4 text-blue-500" />
+            </div>
+            <p className="text-2xl font-bold text-blue-400">{contributorsCount}</p>
+          </Card>
+
+          <Card className="p-6">
+            <div className="flex items-center justify-between mb-2">
+              <h3 className="text-sm text-muted-foreground">Your Contribution</h3>
+              <CheckCircle2 className="h-4 w-4 text-green-500" />
+            </div>
+            <p className="text-2xl font-bold">${myContribution}</p>
+          </Card>
+        </div>
+
+        {/* Progress Bar */}
+        <Card className="p-6 mb-8">
+          <div className="flex justify-between items-center mb-2">
+            <h3 className="text-sm font-medium">Fundraising Progress</h3>
+            <span className="text-sm text-muted-foreground">{progressPercentage().toFixed(1)}%</span>
+          </div>
+          <Progress value={progressPercentage()} className="h-3" />
+          <p className="text-xs text-muted-foreground mt-2">
+            Target: $1,000,000 USDT
+          </p>
+        </Card>
+
+        {/* Contribution Form */}
+        <Card className="p-8 max-w-2xl mx-auto">
+          <h2 className="text-2xl font-bold mb-6">Contribute to Pre-Sale</h2>
+
+          {!selectedAccount ? (
+            <Alert className="border-blue-500/50 bg-blue-500/10">
+              <AlertCircle className="h-4 w-4 text-blue-500" />
+              <AlertDescription className="text-blue-600 dark:text-blue-400">
+                Please connect your PezkuwiChain wallet to participate in the pre-sale.
+              </AlertDescription>
+            </Alert>
+          ) : (
+            <>
+              <div className="mb-4">
+                <label className="block text-sm font-medium mb-2">Your wUSDT Balance</label>
+                <div className="p-3 bg-muted rounded-lg">
+                  <span className="text-lg font-semibold">{balances.USDT} wUSDT</span>
+                </div>
+              </div>
+
+              <div className="mb-4">
+                <label className="block text-sm font-medium mb-2">wUSDT Amount</label>
+                <Input
+                  type="number"
+                  value={wusdtAmount}
+                  onChange={(e) => setWusdtAmount(e.target.value)}
+                  placeholder="100"
+                  min="0"
+                  step="0.01"
+                  disabled={paused || loading}
+                  className="text-lg"
+                />
+                <p className="text-sm text-muted-foreground mt-2">
+                  You will receive: <span className="font-semibold text-green-500">{calculatePezReceived(wusdtAmount).toLocaleString()} PEZ</span>
+                </p>
+              </div>
+
+              <Button
+                onClick={handleContribute}
+                className="w-full"
+                size="lg"
+                disabled={!selectedAccount || !wusdtAmount || paused || loading}
+              >
+                {loading && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+                {loading ? 'Contributing...' : 'Contribute wUSDT'}
+              </Button>
+
+              <div className="mt-6 p-4 bg-muted rounded-lg">
+                <h3 className="font-semibold mb-3 flex items-center">
+                  <CheckCircle2 className="w-4 h-4 mr-2 text-green-500" />
+                  Pre-Sale Terms
+                </h3>
+                <div className="space-y-2 text-sm">
+                  <div className="flex justify-between">
+                    <span className="text-muted-foreground">Conversion Rate:</span>
+                    <span className="font-medium">1 wUSDT = 100 PEZ</span>
+                  </div>
+                  <div className="flex justify-between">
+                    <span className="text-muted-foreground">Distribution:</span>
+                    <span className="font-medium">After 45 days</span>
+                  </div>
+                  <div className="flex justify-between">
+                    <span className="text-muted-foreground">Lock Period:</span>
+                    <span className="font-medium">None</span>
+                  </div>
+                </div>
+              </div>
+
+              {parseFloat(balances.USDT) === 0 && (
+                <Alert className="mt-4 border-yellow-500/50 bg-yellow-500/10">
+                  <AlertCircle className="h-4 w-4 text-yellow-500" />
+                  <AlertDescription className="text-yellow-600 dark:text-yellow-400">
+                    You don't have wUSDT. Please bridge USDT to wUSDT first.
+                  </AlertDescription>
+                </Alert>
+              )}
+            </>
+          )}
+        </Card>
+
+        {/* Info Cards */}
+        <div className="grid md:grid-cols-2 gap-6 mt-8 max-w-4xl mx-auto">
+          <Card className="p-6">
+            <h3 className="font-semibold mb-3">How to Participate</h3>
+            <ol className="space-y-2 text-sm list-decimal list-inside">
+              <li>Connect your PezkuwiChain wallet</li>
+              <li>Ensure you have wUSDT (bridge if needed)</li>
+              <li>Enter the amount you want to contribute</li>
+              <li>Confirm the transaction</li>
+              <li>Receive PEZ after 45 days</li>
+            </ol>
+          </Card>
+
+          <Card className="p-6">
+            <h3 className="font-semibold mb-3">Important Notes</h3>
+            <ul className="space-y-2 text-sm list-disc list-inside text-muted-foreground">
+              <li>Minimum contribution: 1 wUSDT</li>
+              <li>PEZ will be distributed automatically after presale ends</li>
+              <li>Contributions are final and non-refundable</li>
+              <li>Pre-sale duration: 45 days</li>
+            </ul>
+          </Card>
+        </div>
+      </div>
+    </div>
+  );
+}