every multipart upload through /api/<sidecar>/* arrived corrupted. bodyParser ran on
proxy routes and called parseBody for multipart, so hono cached a FormData on the
request; when the proxy then asked for the bytes hono re-serialised them from that
cache with a NEW boundary, while the proxy still forwarded the ORIGINAL content-type
header. header and body disagreed and the far side rejected it with
"Multipart: Unexpected end of form".
bodyParser now skips prefixes owned by createSidecarProxy, which register themselves
so a new sidecar cannot forget. the proxy also forwards the body as a stream instead
of buffering it, which drops the second in-memory copy of every upload.
note the bug report proposed skipping multipart in bodyParser outright; that would
have broken /upload, /file-browser upload and /bug-report, which do read a multipart
body from ctx.get('body').
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>