ci: add comprehensive CI/CD pipeline with 100% coverage enforcement

Created complete CI/CD infrastructure for V2 development:

GitHub Actions Pipeline (.github/workflows/v2-ci.yml):
- Pre-flight checks (branch naming, commit messages)
- Build & dependency validation
- Code quality with 40+ linters (golangci-lint)
- Unit tests with MANDATORY 100% coverage enforcement
- Integration tests with timeout management
- Performance benchmarks (parser < 5ms, detection < 10ms, e2e < 50ms)
- Decimal precision validation
- Modularity validation (component independence)
- Final validation summary with PR comments

Code Quality (.golangci.yml):
- 40+ enabled linters for comprehensive checks
- Cyclomatic complexity limits (max 15)
- Magic number detection
- Security scanning (gosec)
- Style checking with MEV/DEX terminology
- Test file exclusions for appropriate linters

Build Automation (Makefile):
- build, test, test-coverage with 100% enforcement
- lint, fmt, vet, security targets
- deps-download, deps-verify, deps-tidy, deps-check
- validate (full CI/CD locally)
- bench (performance benchmarks)
- check-modularity, check-circular
- Color-coded output for better UX

Git Optimization (.gitattributes):
- LF normalization for cross-platform consistency
- Binary file handling
- Diff settings for Go files
- Merge strategies
- Export-ignore for archives

Git Hooks (.git-hooks/):
- pre-commit: format, tests, vet, secret detection, go.mod tidy
- commit-msg: message format validation
- README with installation instructions
- install-git-hooks.sh script for easy setup

Documentation (docs/planning/05_CI_CD_SETUP.md):
- Complete pipeline architecture diagram
- Local development workflow
- GitHub Actions job descriptions
- Performance optimizations (caching, parallel execution)
- Failure handling and debugging
- Branch protection rules
- Deployment process
- Best practices and troubleshooting

Performance Targets:
- Pipeline duration: < 15 minutes
- Test coverage: 100% (enforced, non-negotiable)
- Parser latency: < 5ms
- Arbitrage detection: < 10ms
- End-to-end: < 50ms

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

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

.git-hooks/pre-commit

@@ -0,0 +1,202 @@
+#!/bin/bash
+#
+# Pre-commit hook for MEV Bot V2
+# Ensures code quality and consistency before commits
+#
+# Install: ln -sf ../../.git-hooks/pre-commit .git/hooks/pre-commit
+#
+
+set -e
+
+# Colors
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+echo -e "${GREEN}🔍 Running pre-commit checks...${NC}"
+echo ""
+
+# ==============================================================================
+# 1. CHECK BRANCH NAME
+# ==============================================================================
+BRANCH_NAME=$(git branch --show-current)
+
+if [[ "$BRANCH_NAME" == "feature/v2-prep" ]] || [[ "$BRANCH_NAME" == "master" ]]; then
+    echo -e "${YELLOW}⚠️  Warning: Committing to protected branch: $BRANCH_NAME${NC}"
+    echo -e "${YELLOW}   Consider creating a feature branch instead${NC}"
+    echo ""
+fi
+
+if [[ "$BRANCH_NAME" =~ ^feature/v2/ ]]; then
+    # Validate branch naming convention
+    if [[ ! "$BRANCH_NAME" =~ ^feature/v2/[a-z0-9-]+/[A-Z0-9]+-[0-9]+-[a-z0-9-]+$ ]]; then
+        echo -e "${YELLOW}⚠️  Branch name doesn't follow convention:${NC}"
+        echo -e "${YELLOW}   feature/v2/<component>/<TASK-ID>-<description>${NC}"
+        echo ""
+    fi
+fi
+
+# ==============================================================================
+# 2. CHECK FOR MERGE CONFLICTS
+# ==============================================================================
+echo -e "${GREEN}📋 Checking for merge conflicts...${NC}"
+if git diff --cached --name-only | xargs grep -l "^<<<<<<< HEAD" 2>/dev/null; then
+    echo -e "${RED}❌ Merge conflict markers found${NC}"
+    echo -e "${RED}   Resolve conflicts before committing${NC}"
+    exit 1
+fi
+echo -e "${GREEN}✅ No merge conflicts${NC}"
+echo ""
+
+# ==============================================================================
+# 3. CHECK FOR FORBIDDEN PATTERNS
+# ==============================================================================
+echo -e "${GREEN}🔒 Checking for secrets and forbidden patterns...${NC}"
+
+# Check for common secret patterns
+if git diff --cached --name-only -z | xargs -0 grep -E "password|secret|api[_-]?key|private[_-]?key|token" --include="*.go" 2>/dev/null | grep -v "test" | grep -v "example"; then
+    echo -e "${RED}❌ Potential secrets found${NC}"
+    echo -e "${RED}   Remove secrets before committing${NC}"
+    exit 1
+fi
+
+# Check for debugging statements
+if git diff --cached --name-only -z | xargs -0 grep -E "fmt\.Println|log\.Println|panic\(|TODO.*URGENT|FIXME.*CRITICAL" --include="*.go" 2>/dev/null; then
+    echo -e "${YELLOW}⚠️  Warning: Found debugging statements or urgent TODOs${NC}"
+    echo -e "${YELLOW}   Consider removing or creating issues for them${NC}"
+    echo ""
+fi
+
+echo -e "${GREEN}✅ No forbidden patterns found${NC}"
+echo ""
+
+# ==============================================================================
+# 4. GO MOD TIDY CHECK
+# ==============================================================================
+if [ -f "go.mod" ]; then
+    echo -e "${GREEN}📦 Checking if go.mod is tidy...${NC}"
+
+    # Save current go.mod and go.sum
+    cp go.mod go.mod.backup
+    cp go.sum go.sum.backup
+
+    # Run go mod tidy
+    go mod tidy
+
+    # Check if anything changed
+    if ! diff -q go.mod go.mod.backup > /dev/null 2>&1 || ! diff -q go.sum go.sum.backup > /dev/null 2>&1; then
+        echo -e "${YELLOW}⚠️  go.mod or go.sum was not tidy${NC}"
+        echo -e "${YELLOW}   Auto-fixed and staged${NC}"
+        git add go.mod go.sum
+    fi
+
+    # Clean up backups
+    rm -f go.mod.backup go.sum.backup
+
+    echo -e "${GREEN}✅ Dependencies are tidy${NC}"
+    echo ""
+fi
+
+# ==============================================================================
+# 5. CODE FORMATTING
+# ==============================================================================
+echo -e "${GREEN}🎨 Checking code formatting...${NC}"
+
+# Get list of staged Go files
+STAGED_GO_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep "\.go$" || true)
+
+if [ -n "$STAGED_GO_FILES" ]; then
+    # Check formatting
+    UNFORMATTED=$(gofmt -l $STAGED_GO_FILES 2>/dev/null || true)
+
+    if [ -n "$UNFORMATTED" ]; then
+        echo -e "${YELLOW}⚠️  Auto-formatting files:${NC}"
+        echo "$UNFORMATTED"
+
+        # Auto-format files
+        echo "$UNFORMATTED" | xargs gofmt -w -s
+
+        # Re-stage formatted files
+        echo "$UNFORMATTED" | xargs git add
+
+        echo -e "${GREEN}✅ Code formatted and re-staged${NC}"
+    else
+        echo -e "${GREEN}✅ All files properly formatted${NC}"
+    fi
+else
+    echo -e "${GREEN}ℹ️  No Go files to format${NC}"
+fi
+echo ""
+
+# ==============================================================================
+# 6. RUN TESTS ON CHANGED FILES
+# ==============================================================================
+if [ -n "$STAGED_GO_FILES" ]; then
+    echo -e "${GREEN}🧪 Running tests on changed packages...${NC}"
+
+    # Get unique package directories
+    PACKAGES=$(echo "$STAGED_GO_FILES" | xargs -n1 dirname | sort -u | sed 's/$/\/.../')
+
+    # Run tests with timeout
+    if ! go test -short -timeout=2m $PACKAGES 2>&1; then
+        echo -e "${RED}❌ Tests failed${NC}"
+        echo -e "${RED}   Fix tests before committing${NC}"
+        exit 1
+    fi
+
+    echo -e "${GREEN}✅ Tests passed${NC}"
+else
+    echo -e "${GREEN}ℹ️  No Go files changed, skipping tests${NC}"
+fi
+echo ""
+
+# ==============================================================================
+# 7. RUN GO VET
+# ==============================================================================
+if [ -n "$STAGED_GO_FILES" ]; then
+    echo -e "${GREEN}🔍 Running go vet...${NC}"
+
+    if ! go vet ./... 2>&1; then
+        echo -e "${RED}❌ go vet found issues${NC}"
+        echo -e "${RED}   Fix issues before committing${NC}"
+        exit 1
+    fi
+
+    echo -e "${GREEN}✅ go vet passed${NC}"
+fi
+echo ""
+
+# ==============================================================================
+# 8. CHECK FILE SIZES
+# ==============================================================================
+echo -e "${GREEN}📏 Checking file sizes...${NC}"
+
+LARGE_FILES=$(git diff --cached --name-only | xargs -I {} sh -c 'if [ -f "{}" ]; then stat -f%z "{}" 2>/dev/null || stat -c%s "{}" 2>/dev/null; fi' | awk '$1 > 1048576 {print}' || true)
+
+if [ -n "$LARGE_FILES" ]; then
+    echo -e "${YELLOW}⚠️  Warning: Large files detected (>1MB)${NC}"
+    echo -e "${YELLOW}   Consider if these should be committed${NC}"
+    git diff --cached --name-only | while read file; do
+        size=$(stat -f%z "$file" 2>/dev/null || stat -c%s "$file" 2>/dev/null)
+        if [ "$size" -gt 1048576 ]; then
+            size_mb=$(echo "scale=2; $size / 1048576" | bc)
+            echo -e "${YELLOW}   $file: ${size_mb}MB${NC}"
+        fi
+    done
+    echo ""
+fi
+
+echo -e "${GREEN}✅ File size check complete${NC}"
+echo ""
+
+# ==============================================================================
+# 9. FINAL SUMMARY
+# ==============================================================================
+echo -e "${GREEN}╔══════════════════════════════════════╗${NC}"
+echo -e "${GREEN}║  ✅ PRE-COMMIT CHECKS PASSED ✅      ║${NC}"
+echo -e "${GREEN}╚══════════════════════════════════════╝${NC}"
+echo ""
+echo -e "${GREEN}Proceeding with commit...${NC}"
+
+exit 0