feat: F6.1 FILIUS files on F: projects from examples and .fls, copies, export

/svc/examples lists FILIUS' examples, which lie beside F in the image (GPL
like this repository, kept out of the dashboard); /svc/projects makes a
project from one; /svc/projects/<id>/import takes a .fls (up to 64 MiB),
/copy copies a project as it is now, /export gives it back as a .fls with its
warnings. Large files go into the blob store on import and come back from it
on export, which is refused when one is missing.

Found on the way: Node's request body is a Buffer, and Yjs takes no Buffer
into a document, so every .fls with binary files would have failed; and
fflate, now in the bundle, imports createRequire itself, which the build's
banner declared again, so F did not start. The banner names it otherwise and
a test builds and starts the bundle. The proxy's /svc/ takes 70 MB.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/Dockerfile

@@ -33,6 +33,8 @@ ENV NODE_ENV=production
 WORKDIR /app
 COPY --from=build /src/packages/server/dist/main.mjs /src/packages/server/dist/simWorker.mjs ./
 COPY --from=build /src/packages/editor/dist ./editor
+# FILIUS' examples, from which the dashboard makes projects (/svc/examples).
+COPY corpus/java-examples ./examples
 COPY LICENSE README.md CHANGES.md ./
 # Not root: F needs no privilege, and a hole in it should not get one.
 USER node