Why this became its own focus area
This site itself is the clearest example β building it surfaced real problems most tutorials skip. A canonical tag left pointing at an old GitHub Pages URL quietly told Google to ignore the real domain. A sitemap referencing pages that didn't exist yet actively hurt indexing rather than helping it. These aren't exotic edge cases; they're the ordinary failure modes of shipping a real site.
Clean code and SEO end up being the same discipline in practice: both reward being precise about what actually exists versus what you assume exists.