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>

.gitattributes

@@ -0,0 +1,79 @@
+# Git attributes for MEV Bot V2
+# Optimizes git operations and ensures consistent handling across platforms
+
+# Auto detect text files and perform LF normalization
+* text=auto
+
+# Source code
+*.go text eol=lf
+*.mod text eol=lf
+*.sum text eol=lf
+*.sh text eol=lf
+*.bash text eol=lf
+
+# Documentation
+*.md text eol=lf
+*.txt text eol=lf
+*.json text eol=lf
+*.yaml text eol=lf
+*.yml text eol=lf
+*.toml text eol=lf
+
+# Configuration
+.gitignore text eol=lf
+.gitattributes text eol=lf
+.golangci.yml text eol=lf
+Makefile text eol=lf
+Dockerfile text eol=lf
+
+# Scripts
+scripts/* text eol=lf
+
+# Binary files
+*.png binary
+*.jpg binary
+*.jpeg binary
+*.gif binary
+*.ico binary
+*.mov binary
+*.mp4 binary
+*.mp3 binary
+*.gz binary
+*.zip binary
+*.tar binary
+*.pdf binary
+
+# Go binaries
+*.exe binary
+*.so binary
+*.dylib binary
+
+# Archives
+*.7z binary
+*.jar binary
+*.rar binary
+*.tar.gz binary
+*.tgz binary
+
+# Exclude files from export-ignore (speeds up git archive)
+.gitattributes export-ignore
+.gitignore export-ignore
+.github export-ignore
+.golangci.yml export-ignore
+*.md export-ignore
+docs export-ignore
+scripts export-ignore
+
+# Git LFS tracking for large files (if needed in future)
+# *.bin filter=lfs diff=lfs merge=lfs -text
+# *.dat filter=lfs diff=lfs merge=lfs -text
+
+# Diff settings
+*.go diff=golang
+*.mod diff=golang
+*.sum diff=golang
+
+# Merge strategies
+*.json merge=ours
+*.lock merge=ours
+go.sum merge=ours