Test Coverage, CLAUDE.md, and README Footer (#39)

* Update CLAUDE.md with expanded Makefile targets and updated commands

Enhance documentation to include detailed descriptions for existing and new Makefile targets, updated build and testing commands, and clarified directory structure for integration and E2E tests.

* Update README with author and sponsorship details

Add attribution to Craig Johnston and sponsorship acknowledgment for Deasil Works, Inc. at the end of the README.

* Add comprehensive test suite for CLI commands and dry-run functionality

Extend test coverage with dry-run tests for `RemoveIPs`, `RemoveCIDRs`, and `RemoveByComment`. Add validation tests for CLI commands, including `add`, `remove`, `list`, and `show` commands, and run function tests to ensure correct command behavior.

Author: cjimti

CLAUDE.md

@@ -18,17 +18,17 @@ txeh is a Go library and CLI utility for managing /etc/hosts file entries. It pr
 
 ```bash
 # Full verification (run before every commit)
-make verify
+make verify          # fmt, lint, test-unit, security, go mod verify
 
-# Run all tests including integration
-make verify-full
+# Extended verification
+make verify-full     # fmt, lint, test, security, go mod verify
 
 # Format, lint, test individually
-make fmt
-make lint
-make test-unit
-make coverage
-make security
+make fmt             # gofmt + goimports
+make lint            # golangci-lint
+make test-unit       # go test -race ./...
+make coverage        # Coverage report (HTML + summary)
+make security        # gosec + govulncheck
 ```
 
 ## Architecture
@@ -141,22 +141,34 @@ entries := hosts.ListHostsByComment("myapp")
 
 ```bash
 # Development
-make build          # Build CLI binary
-make test-unit      # Run unit tests
-make lint           # Run linter
-make fmt            # Format code
+make build          # Build CLI binary to txeh/dist/
+make test-unit      # Run unit tests with race detection
+make lint           # Run golangci-lint
+make lint-fix       # Run golangci-lint with auto-fix
+make fmt            # Format code (gofmt + goimports)
 
 # Before committing
-make verify         # Format, lint, test, security scan
+make verify         # fmt, lint, test-unit, security, go mod verify
 
-# Full CI verification
-make verify-full    # Includes integration tests
+# Extended verification
+make verify-full    # fmt, lint, test, security, go mod verify
+
+# Testing
+make test-integration  # Integration tests (tagged)
+make test-e2e          # E2E tests (tagged, requires Docker)
+make coverage          # Generate coverage report (HTML + summary)
+
+# Code quality
+make security       # gosec + govulncheck
+make dead-code      # Check for unreachable code (deadcode)
+make check          # go vet + staticcheck + golangci-lint
+make mutate         # Mutation testing (gremlins, threshold 60%)
 
 # Debugging
 go test -v -run TestSpecific ./...  # Run specific test
 
-# Build release
-goreleaser --skip-publish --clean --skip-validate
+# Build release (goreleaser v2)
+goreleaser release --snapshot --clean
 ```
 
 ## File Naming Conventions
@@ -165,6 +177,9 @@ goreleaser --skip-publish --clean --skip-validate
 |---------|---------|
 | `*_test.go` | Test files (same package) |
 | `txeh/cmd/*.go` | CLI command implementations |
+| `test/integration/` | Integration tests (`-tags=integration`) |
+| `test/e2e/` | End-to-end tests (`-tags=e2e`) |
+| `GNUmakefile` | Build automation (use `make`) |
 
 ## Git Commit Guidelines
 

README.md

@@ -300,4 +300,8 @@ GITHUB_TOKEN=$GITHUB_TOKEN goreleaser --clean
 
 Apache License 2.0
 
+---
+
+Open source by [Craig Johnston](https://twitter.com/cjimti), sponsored by [Deasil Works, Inc.](https://deasil.works/)
+
 [/etc/hosts]:https://en.wikipedia.org/wiki/Hosts_(file)