CHORE v2.1.0 Release -- review new Makefile Lint violations

[reactive-firewall]

Describe the bug
A clear and concise description of what the bug is.

New checks in checkmake linter has identified 14 new violations in our Makefile

To Reproduce
Steps to reproduce the behavior:

1. Run Makefile Lint
2. Wait for run to compleat ...
3. See error

Expected behavior
A clear and concise description of what you expected to happen.

Logs (optional)
If applicable, add logs here to help explain your problem.

https://github.com/reactive-firewall-org/multicast/actions/runs/19091181958/job/54544252293#step:8:142

Screenshots (optional)
If applicable, add screenshots to help explain your problem.

• Multicast Library Version: v2.1.0 @ 4f30d61

Additional context (optional)
Add any other context about the problem here.

• need to review new checkmake rules and resolve the checks.

[coderabbitai]

A summary of the changes CodeRabbit can apply:

• Add 27 missing phony targets to the Makefile's .PHONY declaration (build, install, user-install, test-style, test-pytest, test-mat, test-mats, test-mat-doctests, test-extra, test-fuzzing, test-perf, test-tox, just-test, test-reqs, cleanup-tests, cleanup-multicast, cleanup-multicast-eggs, cleanup-nested-multicast-eggs, cleanup-py-caches, cleanup-py-cache-dirs, cleanup-src-dir, cleanup-hypothesis, cleanup-mac-dir-store, purge, legacy-purge, purge-coverage-artifacts, purge-test-reports) and convert five double-colon rules to single-colon (branding, purge-test-reports, cleanup-dev-backups, cleanup-mac-dir-store, cleanup-hypothesis) to resolve checkmake lint violations without changing behavior.

• Update Makefile: expand the .PHONY target to add numerous build/install/test/cleanup targets and normalize several target declarations (change branding, purge-test-reports, cleanup-dev-backups, cleanup-mac-dir-store, cleanup-hypothesis from '::' to ':') while preserving their recipe contents.

• Generated copyable edits - (🔄 Check again to refresh)

[coderabbitai]

Caution

The CodeRabbit agent's plans did not produce any file changes.

[mikelolasagasti]

This should be fixed with this change to checkmake: checkmake/checkmake#190

I've been using this project's Makefile to verify that new code doesn't break stuff.