feat: create v2-prep branch with comprehensive planning

Restructured project for V2 refactor:

**Structure Changes:**
- Moved all V1 code to orig/ folder (preserved with git mv)
- Created docs/planning/ directory
- Added orig/README_V1.md explaining V1 preservation

**Planning Documents:**
- 00_V2_MASTER_PLAN.md: Complete architecture overview
  - Executive summary of critical V1 issues
  - High-level component architecture diagrams
  - 5-phase implementation roadmap
  - Success metrics and risk mitigation

- 07_TASK_BREAKDOWN.md: Atomic task breakdown
  - 99+ hours of detailed tasks
  - Every task < 2 hours (atomic)
  - Clear dependencies and success criteria
  - Organized by implementation phase

**V2 Key Improvements:**
- Per-exchange parsers (factory pattern)
- Multi-layer strict validation
- Multi-index pool cache
- Background validation pipeline
- Comprehensive observability

**Critical Issues Addressed:**
- Zero address tokens (strict validation + cache enrichment)
- Parsing accuracy (protocol-specific parsers)
- No audit trail (background validation channel)
- Inefficient lookups (multi-index cache)
- Stats disconnection (event-driven metrics)

Next Steps:
1. Review planning documents
2. Begin Phase 1: Foundation (P1-001 through P1-010)
3. Implement parsers in Phase 2
4. Build cache system in Phase 3
5. Add validation pipeline in Phase 4
6. Migrate and test in Phase 5

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

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

orig/pkg/contracts/key_manager.go

@@ -0,0 +1,57 @@
+package contracts
+
+import (
+	"crypto/ecdsa"
+	"encoding/hex"
+	"fmt"
+	"os"
+
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+type KeyManager struct {
+	privateKey *ecdsa.PrivateKey
+}
+
+// NewKeyManager creates a new key manager from environment
+func NewKeyManager() (*KeyManager, error) {
+	privateKeyStr := os.Getenv("PRIVATE_KEY")
+	if privateKeyStr == "" {
+		return nil, fmt.Errorf("PRIVATE_KEY environment variable not set")
+	}
+
+	// Remove 0x prefix if present
+	if len(privateKeyStr) > 2 && privateKeyStr[:2] == "0x" {
+		privateKeyStr = privateKeyStr[2:]
+	}
+
+	privateKeyBytes, err := hex.DecodeString(privateKeyStr)
+	if err != nil {
+		return nil, fmt.Errorf("invalid private key: %v", err)
+	}
+
+	privateKey, err := crypto.ToECDSA(privateKeyBytes)
+	if err != nil {
+		return nil, fmt.Errorf("invalid private key format: %v", err)
+	}
+
+	return &KeyManager{
+		privateKey: privateKey,
+	}, nil
+}
+
+// GetPrivateKey returns the private key
+func (km *KeyManager) GetPrivateKey() (*ecdsa.PrivateKey, error) {
+	if km.privateKey == nil {
+		return nil, fmt.Errorf("private key not initialized")
+	}
+	return km.privateKey, nil
+}
+
+// GetAddress returns the Ethereum address
+func (km *KeyManager) GetAddress() string {
+	if km.privateKey == nil {
+		return ""
+	}
+	return crypto.PubkeyToAddress(km.privateKey.PublicKey).Hex()
+}