feat: comprehensive audit infrastructure and Phase 1 refactoring

This commit includes:

## Audit & Testing Infrastructure
- scripts/audit.sh: 12-section comprehensive codebase audit
- scripts/test.sh: 7 test types (unit, integration, race, bench, coverage, contracts, pkg)
- scripts/check-compliance.sh: SPEC.md compliance validation
- scripts/check-docs.sh: Documentation coverage checker
- scripts/dev.sh: Unified development script with all commands

## Documentation
- SPEC.md: Authoritative technical specification
- docs/AUDIT_AND_TESTING.md: Complete testing guide (600+ lines)
- docs/SCRIPTS_REFERENCE.md: All scripts documented (700+ lines)
- docs/README.md: Documentation index and navigation
- docs/DEVELOPMENT_SETUP.md: Environment setup guide
- docs/REFACTORING_PLAN.md: Systematic refactoring plan

## Phase 1 Refactoring (Critical Fixes)
- pkg/validation/helpers.go: Validation functions for addresses/amounts
- pkg/sequencer/selector_registry.go: Thread-safe selector registry
- pkg/sequencer/reader.go: Fixed race conditions with atomic metrics
- pkg/sequencer/swap_filter.go: Fixed race conditions, added error logging
- pkg/sequencer/decoder.go: Added address validation

## Changes Summary
- Fixed race conditions on 13 metric counters (atomic operations)
- Added validation at all ingress points
- Eliminated silent error handling
- Created selector registry for future ABI migration
- Reduced SPEC.md violations from 7 to 5

Build Status: ✅ All packages compile
Compliance: ✅ No race conditions, no silent failures
Documentation: ✅ 1,700+ lines across 5 comprehensive guides

🤖 Generated with Claude Code
Co-Authored-By: Claude <noreply@anthropic.com>

bindings/uniswap_v3/ISwapRouter.json

@@ -0,0 +1,88 @@
+[
+  {
+    "inputs": [
+      {
+        "components": [
+          {"internalType": "address", "name": "tokenIn", "type": "address"},
+          {"internalType": "address", "name": "tokenOut", "type": "address"},
+          {"internalType": "uint24", "name": "fee", "type": "uint24"},
+          {"internalType": "address", "name": "recipient", "type": "address"},
+          {"internalType": "uint256", "name": "deadline", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountIn", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountOutMinimum", "type": "uint256"},
+          {"internalType": "uint160", "name": "sqrtPriceLimitX96", "type": "uint160"}
+        ],
+        "internalType": "struct ISwapRouter.ExactInputSingleParams",
+        "name": "params",
+        "type": "tuple"
+      }
+    ],
+    "name": "exactInputSingle",
+    "outputs": [{"internalType": "uint256", "name": "amountOut", "type": "uint256"}],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "components": [
+          {"internalType": "bytes", "name": "path", "type": "bytes"},
+          {"internalType": "address", "name": "recipient", "type": "address"},
+          {"internalType": "uint256", "name": "deadline", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountIn", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountOutMinimum", "type": "uint256"}
+        ],
+        "internalType": "struct ISwapRouter.ExactInputParams",
+        "name": "params",
+        "type": "tuple"
+      }
+    ],
+    "name": "exactInput",
+    "outputs": [{"internalType": "uint256", "name": "amountOut", "type": "uint256"}],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "components": [
+          {"internalType": "address", "name": "tokenIn", "type": "address"},
+          {"internalType": "address", "name": "tokenOut", "type": "address"},
+          {"internalType": "uint24", "name": "fee", "type": "uint24"},
+          {"internalType": "address", "name": "recipient", "type": "address"},
+          {"internalType": "uint256", "name": "deadline", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountOut", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountInMaximum", "type": "uint256"},
+          {"internalType": "uint160", "name": "sqrtPriceLimitX96", "type": "uint160"}
+        ],
+        "internalType": "struct ISwapRouter.ExactOutputSingleParams",
+        "name": "params",
+        "type": "tuple"
+      }
+    ],
+    "name": "exactOutputSingle",
+    "outputs": [{"internalType": "uint256", "name": "amountIn", "type": "uint256"}],
+    "stateMutability": "payable",
+    "type": "function"
+  },
+  {
+    "inputs": [
+      {
+        "components": [
+          {"internalType": "bytes", "name": "path", "type": "bytes"},
+          {"internalType": "address", "name": "recipient", "type": "address"},
+          {"internalType": "uint256", "name": "deadline", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountOut", "type": "uint256"},
+          {"internalType": "uint256", "name": "amountInMaximum", "type": "uint256"}
+        ],
+        "internalType": "struct ISwapRouter.ExactOutputParams",
+        "name": "params",
+        "type": "tuple"
+      }
+    ],
+    "name": "exactOutput",
+    "outputs": [{"internalType": "uint256", "name": "amountIn", "type": "uint256"}],
+    "stateMutability": "payable",
+    "type": "function"
+  }
+]