* fix(uploads): stop deleting a converted companion we cannot prove we wrote
Conversion names a document's Markdown companion after the document's
stem and falls back to a _N suffix when that name is already taken, so
the .md beside a document may belong to another document sharing the
stem, or to the user. Delete removed it anyway: uploading a.docx and
a.pdf produces a.md and a_1.md, and deleting a.pdf destroyed a.docx's
companion while orphaning a.pdf's own.
Delete now removes only the file it was asked to remove. The companion
stays listed and can be deleted on its own. Orphans are the cost of not
guessing; issue #5672 covers giving companions a provable owner, which
is what a safe cleanup needs, along with the two related readers that
still guess (the outline injected for a document and the agent's file
listing).
convertible_extensions loses its last use and is dropped from the
signature and both call sites. The gateway router keeps importing
CONVERTIBLE_EXTENSIONS for the ingestion bridge and now declares it in
__all__, where that module documents its re-exports.
* docs(changelog): note that delete keeps the converted markdown (#5673)