Fixes #4032.
Refs #4014.

Summary

• replace the separate --livereload / --no-livereload flag_value options with Click's paired boolean option form
• keep mkdocs serve defaulting to livereload=True on Click 8.3.0, so watch paths are registered again
• exclude Click 8.2.2 because that yanked release still corrupts several MkDocs CLI defaults (build_type, strict, use_directory_urls), not just livereload

Verification

• red before the CLI flag change, with Click 8.3.0: CLITests.test_serve_default passed livereload=False into mkdocs.commands.serve.serve
• C:\hades\oss\.venvs\mkdocs-4032-click830\Scripts\python.exe -m unittest mkdocs.tests.cli_tests with Click 8.3.0: 37 passed
• C:\hades\oss\.venvs\mkdocs-4045\Scripts\python.exe -m unittest mkdocs.tests.cli_tests with Click 8.4.1: 37 passed
• C:\hades\oss\.venvs\mkdocs-4045\Scripts\python.exe -m black --check --diff --target-version py313 mkdocs\__main__.py: passed
• C:\hades\oss\.venvs\mkdocs-4045\Scripts\isort.exe --check-only --diff mkdocs\__main__.py: passed
• git diff --check: passed

Note: ruff check mkdocs\__main__.py reports pre-existing lazy-import/style findings in this file that are outside this patch; ruff check --diff mkdocs\__main__.py reports no fixable diff.