docs(blog): rewrite the provenance post for readability

The two failures that retired the word-boundary tier were described with the
internal variable names they happened to involve, which carry no meaning outside
the codebase and read like a bug ticket. They are now described by shape — a
small number stored as a retry limit, a feature flag holding false — which is the
same lesson in a form a reader recognizes.

Style pass over the whole post alongside it: connective tissue between sections
rather than cold starts, second person where the reader is being addressed as a
builder, and longer explanatory sentences mixed back in among the short
declaratives, which had accumulated into a run of pronouncements. Section
headings take the descriptive "Topic: Detail" form the executor post uses.

No technical claim changed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: icecrasher321