docs(presale): add comprehensive presale documentation

Created three documentation files:

1. PRESALE_README.md - Quick overview and status
   - All 5 phases completed
   - Architecture diagram
   - File locations
   - Quick start guides

2. docs/presale/PRESALE_GUIDE.md - Complete user & admin guide
   - Step-by-step participation guide
   - Admin management (start/monitor/finalize)
   - Emergency procedures
   - Technical details and calculations
   - FAQs and troubleshooting

3. docs/presale/PRESALE_TESTING.md - Testing checklist
   - Pallet tests (backend logic)
   - Frontend tests (UI/UX)
   - Integration tests (end-to-end)
   - Performance and security checks

All documentation reflects:
- Conversion rate: 1 wUSDT = 20 PEZ
- Duration: 45 days
- Max contributors: 10,000
- Pure pallet implementation (no smart contract)

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

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

docs/presale/PRESALE_TESTING.md

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+# Presale System Testing Checklist
+
+## Test Environment Setup
+- [ ] Runtime compiled with presale pallet
+- [ ] Frontend build successful
+- [ ] Dev node running
+- [ ] Test accounts with wUSDT funded
+
+## Pallet Tests (Backend)
+
+### 1. Start Presale
+- [ ] Only sudo can start presale
+- [ ] PresaleActive storage updated to true
+- [ ] PresaleStartBlock recorded
+- [ ] PresaleStarted event emitted
+- [ ] Cannot start if already started
+
+### 2. Contribute
+- [ ] User can contribute wUSDT
+- [ ] wUSDT transferred from user to treasury
+- [ ] Contribution recorded in Contributions storage
+- [ ] Contributor added to Contributors list (first time)
+- [ ] TotalRaised incremented correctly
+- [ ] Contributed event emitted
+- [ ] Cannot contribute zero amount
+- [ ] Cannot contribute if presale not active
+- [ ] Cannot contribute if presale ended
+- [ ] Cannot contribute if paused
+
+### 3. Finalize Presale
+- [ ] Only sudo can finalize
+- [ ] Cannot finalize before presale ends
+- [ ] PEZ distributed to all contributors
+- [ ] Distribution calculation correct (1 wUSDT = 20 PEZ)
+- [ ] Decimal conversion correct (wUSDT 6 decimals → PEZ 12 decimals)
+- [ ] PresaleActive set to false
+- [ ] PresaleFinalized event emitted
+- [ ] Distributed events for each contributor
+
+### 4. Emergency Functions
+- [ ] Only sudo can pause
+- [ ] Paused flag prevents contributions
+- [ ] Only sudo can unpause
+- [ ] EmergencyPaused/Unpaused events emitted
+
+### 5. Edge Cases
+- [ ] Multiple contributions from same user accumulate
+- [ ] Large numbers don't overflow
+- [ ] Contributors list doesn't exceed MaxContributors
+- [ ] Treasury has sufficient PEZ for distribution
+
+## Frontend Tests (UI)
+
+### 1. Pre-Sale Not Started
+- [ ] Shows "not started" message
+- [ ] Displays pre-sale details (duration, rate, token)
+- [ ] No contribution form visible
+
+### 2. Pre-Sale Active
+- [ ] Stats grid displays:
+  - [ ] Time remaining (countdown)
+  - [ ] Total raised (in USDT)
+  - [ ] Contributors count
+  - [ ] User's contribution
+- [ ] Progress bar shows percentage
+- [ ] Conversion rate displays correctly (1 wUSDT = 20 PEZ)
+
+### 3. Contribution Form
+- [ ] Wallet connection required
+- [ ] wUSDT balance displayed
+- [ ] Amount input validation
+- [ ] PEZ calculation preview (amount × 20)
+- [ ] Submit button disabled when:
+  - [ ] No wallet connected
+  - [ ] No amount entered
+  - [ ] Presale paused
+  - [ ] Loading state
+- [ ] Success toast on contribution
+- [ ] Error toast on failure
+- [ ] Balance warning if insufficient wUSDT
+
+### 4. Paused State
+- [ ] Yellow alert banner shows
+- [ ] Contribution disabled
+- [ ] Message: "temporarily paused"
+
+### 5. Real-time Updates
+- [ ] Data refreshes every 10 seconds
+- [ ] Countdown updates
+- [ ] Stats update after contribution
+- [ ] No memory leaks (interval cleanup)
+
+## Integration Tests
+
+### 1. End-to-End Flow
+- [ ] User bridges USDT to wUSDT
+- [ ] Connects wallet to presale page
+- [ ] Enters contribution amount
+- [ ] Transaction signed and submitted
+- [ ] Contribution recorded on-chain
+- [ ] UI updates with new values
+- [ ] After 45 days, receives PEZ
+
+### 2. Multi-User Scenario
+- [ ] Multiple users contribute
+- [ ] Contributors count increases
+- [ ] Total raised accumulates
+- [ ] Each user sees own contribution
+- [ ] Finalization distributes to all
+
+### 3. Error Scenarios
+- [ ] Insufficient wUSDT balance → error toast
+- [ ] Network error → retry mechanism
+- [ ] Transaction rejected → graceful failure
+- [ ] Invalid amount → validation error
+
+## Performance Tests
+
+- [ ] Load time acceptable (<3s)
+- [ ] Transaction completion time (<30s)
+- [ ] Query performance with 1000+ contributors
+- [ ] Frontend responsive on mobile
+- [ ] No console errors
+- [ ] Build size reasonable
+
+## Security Checks
+
+- [ ] Only root can start/finalize/pause
+- [ ] Users can't withdraw contributed wUSDT
+- [ ] PEZ distribution only after 45 days
+- [ ] No integer overflow in calculations
+- [ ] Treasury account properly secured
+- [ ] Events emitted for audit trail
+
+## Documentation
+
+- [ ] README explains presale process
+- [ ] User guide for participation
+- [ ] Admin guide for starting/finalizing
+- [ ] API documentation for extrinsics
+- [ ] Frontend component documentation
+
+## Deployment Checklist
+
+- [ ] Runtime upgrade tested on testnet
+- [ ] Frontend deployed to staging
+- [ ] Conversion rate confirmed (20x)
+- [ ] Treasury pre-funded with PEZ
+- [ ] Monitoring alerts configured
+- [ ] Backup plan for emergencies
+
+## Known Issues / Limitations
+
+- Mock runtime tests disabled (frame_system compatibility)
+- Benchmarks use estimated weights (not real hardware)
+- Max 10,000 contributors (MaxContributors limit)
+
+## Test Results
+
+| Test Category | Pass | Fail | Notes |
+|--------------|------|------|-------|
+| Pallet Logic | TBD  | TBD  |       |
+| Frontend UI  | TBD  | TBD  |       |
+| Integration  | TBD  | TBD  |       |
+| Performance  | TBD  | TBD  |       |
+| Security     | TBD  | TBD  |       |
+
+---
+
+**Testing Status**: In Progress
+**Last Updated**: 2025-01-20
+**Tester**: Claude Code