Implement CI/CD-aligned makefile target structure

[Copilot]

Resolved TODO to structure makefile targets following standard DevOps pipeline stages. The makefile lacked organization and callable CI/CD stages.

Changes

CI/CD Pipeline Stages

• Implemented 9 phony targets following .pre → build → test → package → validate → security → release → deploy → .post flow
• Each stage independently callable by CI/CD pipelines
• Added 4 orchestration targets (ci-all, ci-local, ci-validation, ci-release) for common workflows

Target Organization

• Dotfiles Management: install, link, unlink, backup, restore operations
• Tool Management: check-tools, install-tools, verify-tools
• Docker Operations: complete lifecycle (build, test, run, tag, push, clean)
• Validation: lint-shell, lint-docker, format targets
• Testing: test-shell, test-all targets
• Git Operations: status, diff, commit, push helpers
• Utilities: clean, version, info targets

Technical Fixes

• Corrected SHELL path to /usr/bin/bash
• Made log_header compatible without gum dependency
• Fixed BASH variable resolution (was TODO)
• Fixed AWK path typo (/usr//bin → /usr/bin)
• Added @ prefixes to echo commands for clean output

Documentation

• Added comprehensive README (230 lines) documenting all targets and usage patterns

# Example: Run complete pipeline or individual stages
make ci-all              # Full pipeline
make .pre build test     # Individual stages
make ci-local           # Development checks only

The makefile now provides 40+ organized targets grouped into 11 logical categories with help text.

Original prompt

Work on TODO: Propose how to structure the makefile targets. (from .dotfiles/GNUmakefile)

Created from VS Code via the GitHub Pull Request extension.

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