fix: copy foundry-module directory into Docker runtime image

The foundry-module/ directory was never copied into the final Docker
stage, so the /foundry-module/module.json endpoint returned 404 in
production despite the handler code being present.

https://claude.ai/code/session_01XMwxFR8BCi5XvgaSVMSBZB

Author: claude

Dockerfile

@@ -60,6 +60,9 @@ COPY --from=builder /src/static /app/static
 # Copy database migrations for auto-migration on startup.
 COPY --from=builder /src/db/migrations /app/db/migrations
 
+# Copy Foundry VTT module files for direct installation from this instance.
+COPY --from=builder /src/foundry-module /app/foundry-module
+
 # Create persistent data directory owned by the chronicle user.
 # Media uploads go under /app/data/media (matches MEDIA_PATH default "./data/media").
 # Mount a volume at /app/data to persist media across container rebuilds.