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>

.golangci.yml

@@ -0,0 +1,245 @@
+run:
+  timeout: 10m
+  tests: true
+  modules-download-mode: readonly
+
+linters:
+  enable:
+    # Enabled by default
+    - errcheck      # Unchecked errors
+    - gosimple      # Simplify code
+    - govet         # Suspicious constructs
+    - ineffassign   # Ineffectual assignments
+    - staticcheck   # Go static analysis
+    - typecheck     # Type checking
+    - unused        # Unused code
+
+    # Additional linters for V2
+    - bodyclose     # Close HTTP response bodies
+    - cyclop        # Cyclomatic complexity
+    - dupl          # Duplicate code
+    - errname       # Error naming conventions
+    - exhaustive    # Exhaustive switch statements
+    - exportloopref # Loop variable references
+    - gochecknoinits # No init functions
+    - gocognit      # Cognitive complexity
+    - goconst       # Repeated strings as constants
+    - gocritic      # Comprehensive checks
+    - gocyclo       # Cyclomatic complexity
+    - godot         # Comment punctuation
+    - gofmt         # Format code
+    - goimports     # Import organization
+    - gomnd         # Magic numbers
+    - goprintffuncname # Printf-like function naming
+    - gosec         # Security issues
+    - lll           # Long lines
+    - makezero      # Slice initialization
+    - misspell      # Misspellings
+    - nakedret      # Naked returns
+    - nestif        # Deeply nested if statements
+    - nilerr        # Nil error returns
+    - noctx         # HTTP requests without context
+    - nolintlint    # Nolint directives
+    - prealloc      # Slice preallocation
+    - predeclared   # Predeclared identifier shadowing
+    - revive        # Golint replacement
+    - rowserrcheck  # SQL rows.Err checking
+    - sqlclosecheck # SQL Close() checking
+    - stylecheck    # Style checking
+    - thelper       # Test helper detection
+    - unconvert     # Unnecessary type conversions
+    - unparam       # Unused function parameters
+    - wastedassign  # Wasted assignments
+    - whitespace    # Whitespace issues
+
+linters-settings:
+  cyclop:
+    max-complexity: 15
+    skip-tests: true
+
+  gocognit:
+    min-complexity: 20
+
+  gocyclo:
+    min-complexity: 15
+
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+    ignore-tests: true
+
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+
+  goimports:
+    local-prefixes: github.com/your-org/mev-bot
+
+  gomnd:
+    settings:
+      mnd:
+        checks:
+          - argument
+          - case
+          - condition
+          - operation
+          - return
+          - assign
+        ignored-numbers:
+          - '0'
+          - '1'
+          - '2'
+          - '10'
+          - '100'
+          - '1000'
+        ignored-functions:
+          - 'big.NewInt'
+          - 'big.NewFloat'
+          - 'time.After'
+          - 'time.Sleep'
+          - 'time.Duration'
+
+  gosec:
+    severity: medium
+    confidence: medium
+    excludes:
+      - G104  # Audit errors not checked (handled by errcheck)
+      - G304  # File path provided as taint input (false positives)
+
+  lll:
+    line-length: 120
+    tab-width: 4
+
+  misspell:
+    locale: US
+    ignore-words:
+      - arbitrum
+      - uniswap
+      - camelot
+
+  nakedret:
+    max-func-lines: 30
+
+  nestif:
+    min-complexity: 4
+
+  revive:
+    rules:
+      - name: blank-imports
+      - name: context-as-argument
+      - name: context-keys-type
+      - name: dot-imports
+      - name: error-return
+      - name: error-strings
+      - name: error-naming
+      - name: exported
+      - name: if-return
+      - name: increment-decrement
+      - name: var-naming
+      - name: var-declaration
+      - name: package-comments
+      - name: range
+      - name: receiver-naming
+      - name: time-naming
+      - name: unexported-return
+      - name: indent-error-flow
+      - name: errorf
+      - name: empty-block
+      - name: superfluous-else
+      - name: unused-parameter
+      - name: unreachable-code
+      - name: redefines-builtin-id
+
+  stylecheck:
+    checks: ["all", "-ST1000", "-ST1003"]
+    dot-import-whitelist:
+      - fmt
+    initialisms:
+      - ACL
+      - API
+      - ASCII
+      - CPU
+      - CSS
+      - DNS
+      - EOF
+      - GUID
+      - HTML
+      - HTTP
+      - HTTPS
+      - ID
+      - IP
+      - JSON
+      - QPS
+      - RAM
+      - RPC
+      - SLA
+      - SMTP
+      - SQL
+      - SSH
+      - TCP
+      - TLS
+      - TTL
+      - UDP
+      - UI
+      - GID
+      - UID
+      - UUID
+      - URI
+      - URL
+      - UTF8
+      - VM
+      - XML
+      - XMPP
+      - XSRF
+      - XSS
+      - ABI
+      - DEX
+      - MEV
+      - RLP
+
+  unparam:
+    check-exported: false
+
+issues:
+  exclude-use-default: false
+  exclude-rules:
+    # Exclude some linters from running on tests files
+    - path: _test\.go
+      linters:
+        - gocyclo
+        - errcheck
+        - dupl
+        - gosec
+        - goconst
+        - gomnd
+        - lll
+
+    # Exclude known issues
+    - path: pkg/legacy/
+      linters:
+        - staticcheck
+        - gocritic
+
+    # Exclude duplicate code in protocol parsers (expected similarity)
+    - path: pkg/parsers/
+      linters:
+        - dupl
+
+    # Allow long lines in generated code
+    - path: pkg/generated/
+      linters:
+        - lll
+
+  max-issues-per-linter: 0
+  max-same-issues: 0
+
+output:
+  format: colored-line-number
+  print-issued-lines: true
+  print-linter-name: true
+  uniq-by-line: true
+  sort-results: true