Convert Image, and HEIC opens because av-club already knew how

the fourth task. same shape as the other three — beside the original, skip an
existing output, skip a file already in the target format, delete only when asked
and only after the write.

/v1/sharp gets the same path mode /v1/ffmpeg got, for the same reason: the file
browser and the commander both already have the file.

HEIC IS THE POINT OF THIS ONE, and nothing in the task does anything about it.
`decodable.ts` has routed HEIC through ImageMagick since before I touched this
plugin, because the libheif inside sharp is built without the HEVC decoder — a
HEIC reads its own header fine and then fails on the pixels, which looks exactly
like a corrupt file and is not one. the task simply names `.heic` in its trigger
and asks. the photographs open.

I had diagnosed that gap independently against the file browser's thumbnails and
concluded a system decoder would be needed, twice telling the owner these files
could not be read. this plugin had already solved it and documented why. worth the
note: the answer was in the tree.

a path has no stored `format`, so sharp's `metadata()` supplies it — and that only
reads the header, which is precisely the part of a HEIC that works, so it correctly
identifies the files needing ImageMagick.

`rotate` with no argument is in every pipeline: it applies the EXIF orientation and
drops the tag. without it a portrait photo from a phone converts to a landscape
image that viewers rotate back, until one does not.

max_dimension shrinks to fit and never enlarges. quality 82 for jpeg and webp, 55
for avif — where a photograph stops looking better and only gets bigger.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

sidecar/index.ts

@@ -193,6 +193,7 @@ async function route(request: Request): Promise<Response> {
       throw invalid("Expected a JSON body");
     })) as SharpRequest;
     const result = await withSlot(() => runSharp(body));
+    if (!("id" in result)) return Response.json(result, { status: 200 });
     return Response.json(result, { status: 201 });
   }