Swagger UI's endpoint-list row already shows the HTTP method badge +
path for every row, so restating `METHOD /path` at the start of a
handler's own summary is pure duplication. Strips that self-referential
prefix from every summary that has it and re-capitalizes what follows
as a standalone sentence.
Left two false positives untouched: misc_api.rs's operator-inbox
summary cross-references a *different* sibling endpoint
(mark-all-read) for context, and topology.rs's SetParentForm struct
doc happens to mention its endpoint's path but isn't a handler summary
line. Both are legitimate, not redundant.