fix(multicall): resolve critical multicall parsing corruption issues

- Added comprehensive bounds checking to prevent buffer overruns in multicall parsing
- Implemented graduated validation system (Strict/Moderate/Permissive) to reduce false positives
- Added LRU caching system for address validation with 10-minute TTL
- Enhanced ABI decoder with missing Universal Router and Arbitrum-specific DEX signatures
- Fixed duplicate function declarations and import conflicts across multiple files
- Added error recovery mechanisms with multiple fallback strategies
- Updated tests to handle new validation behavior for suspicious addresses
- Fixed parser test expectations for improved validation system
- Applied gofmt formatting fixes to ensure code style compliance
- Fixed mutex copying issues in monitoring package by introducing MetricsSnapshot
- Resolved critical security vulnerabilities in heuristic address extraction
- Progress: Updated TODO audit from 10% to 35% complete

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

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

docs/master-plan/02-common-interfaces.md

@@ -0,0 +1,92 @@
+# Common Interfaces for Exchange Modules
+
+## Overview
+
+This document defines the common interfaces that all exchange-specific modules should implement to ensure consistency across the MEV bot.
+
+## Core Interface
+
+```go
+type Exchange interface {
+    // Swap operations
+    Swap(fromToken, toToken string, amount *big.Int) (*SwapResult, error)
+    SwapExactIn(fromToken, toToken string, amountIn *big.Int) (*SwapResult, error)
+    SwapExactOut(fromToken, toToken string, amountOut *big.Int) (*SwapResult, error)
+    
+    // Liquidity operations
+    AddLiquidity(tokenA, tokenB string, amountADesired, amountBDesired *big.Int) (*LiquidityResult, error)
+    RemoveLiquidity(tokenA, tokenB string, liquidity *big.Int) (*LiquidityResult, error)
+    
+    // Pricing functions
+    GetPrice(fromToken, toToken string, amount *big.Int) (*big.Int, error)
+    GetAmountsOut(amountIn *big.Int, path []string) ([]*big.Int, error)
+    GetAmountsIn(amountOut *big.Int, path []string) ([]*big.Int, error)
+    
+    // Pool information
+    GetPoolReserves(tokenA, tokenB string) (*big.Int, *big.Int, error)
+    GetPair(tokenA, tokenB string) (common.Address, error)
+    
+    // Pool management
+    GetAllPools() []Pool
+    GetPoolByAddress(address common.Address) (Pool, error)
+    
+    // Fee calculations
+    GetSwapFee() (*big.Int, error)
+    CalculateSlippage(amount *big.Int, slippagePercent float64) (*big.Int, error)
+}
+```
+
+## Swap Result Structure
+
+```go
+type SwapResult struct {
+    FromToken      string
+    ToToken        string
+    AmountIn       *big.Int
+    AmountOut      *big.Int
+    ExpectedAmount *big.Int
+    GasEstimate    *big.Int
+    Route          []string
+}
+```
+
+## Liquidity Result Structure
+
+```go
+type LiquidityResult struct {
+    TokenA         string
+    TokenB         string
+    AmountA        *big.Int
+    AmountB        *big.Int
+    Liquidity      *big.Int
+    GasEstimate    *big.Int
+}
+```
+
+## Pool Structure
+
+```go
+type Pool struct {
+    Address   common.Address
+    Token0    string
+    Token1    string
+    Reserve0  *big.Int
+    Reserve1  *big.Int
+    Fee       *big.Int
+}
+```
+
+## Error Handling
+
+- All functions should return standardized errors
+- Network-related errors should be distinguishable
+- Invalid input errors should be clearly identified
+- Slippage tolerance exceeded errors should be handled
+
+## Implementation Guidelines
+
+1. All external calls should be properly validated
+2. Input parameters should be sanitized before use
+3. Gas estimation should be performed where possible
+4. Proper timeout handling for external calls
+5. Fallback mechanisms for critical operations