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/arbitrum/parser/executor.go

@@ -0,0 +1,92 @@
+package parser
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	logpkg "github.com/fraktal/mev-beta/internal/logger"
+	pkgtypes "github.com/fraktal/mev-beta/pkg/types"
+)
+
+// OpportunityDispatcher represents the arbitrage service entry point that can
+// accept opportunities discovered by the transaction analyzer.
+type OpportunityDispatcher interface {
+	SubmitBridgeOpportunity(ctx context.Context, bridgeOpportunity interface{}) error
+}
+
+// Executor routes arbitrage opportunities discovered in the Arbitrum parser to
+// the core arbitrage service.
+type Executor struct {
+	logger      *logpkg.Logger
+	dispatcher  OpportunityDispatcher
+	metrics     *ExecutorMetrics
+	serviceName string
+}
+
+// ExecutorMetrics captures lightweight counters about dispatched opportunities.
+type ExecutorMetrics struct {
+	OpportunitiesForwarded int64
+	OpportunitiesRejected  int64
+	LastDispatchTime       time.Time
+}
+
+// NewExecutor creates a new parser executor that forwards opportunities to the
+// provided dispatcher (typically the arbitrage service).
+func NewExecutor(dispatcher OpportunityDispatcher, log *logpkg.Logger) *Executor {
+	if log == nil {
+		log = logpkg.New("info", "text", "")
+	}
+
+	return &Executor{
+		logger:     log,
+		dispatcher: dispatcher,
+		metrics: &ExecutorMetrics{
+			OpportunitiesForwarded: 0,
+			OpportunitiesRejected:  0,
+		},
+		serviceName: "arbitrum-parser",
+	}
+}
+
+// ExecuteArbitrage forwards the opportunity to the arbitrage service.
+func (e *Executor) ExecuteArbitrage(ctx context.Context, arbOp *pkgtypes.ArbitrageOpportunity) error {
+	if arbOp == nil {
+		e.metrics.OpportunitiesRejected++
+		return fmt.Errorf("arbitrage opportunity cannot be nil")
+	}
+
+	if e.dispatcher == nil {
+		e.metrics.OpportunitiesRejected++
+		return fmt.Errorf("no dispatcher configured for executor")
+	}
+
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	e.logger.Info("Forwarding arbitrage opportunity detected by parser",
+		"id", arbOp.ID,
+		"path_length", len(arbOp.Path),
+		"pools", len(arbOp.Pools),
+		"profit", arbOp.NetProfit,
+	)
+
+	if err := e.dispatcher.SubmitBridgeOpportunity(ctx, arbOp); err != nil {
+		e.metrics.OpportunitiesRejected++
+		e.logger.Error("Failed to forward arbitrage opportunity",
+			"id", arbOp.ID,
+			"error", err,
+		)
+		return err
+	}
+
+	e.metrics.OpportunitiesForwarded++
+	e.metrics.LastDispatchTime = time.Now()
+	return nil
+}
+
+// Metrics returns a snapshot of executor metrics.
+func (e *Executor) Metrics() ExecutorMetrics {
+	return *e.metrics
+}