ClamAV ships with StreamMaxLength=25 MB, MaxFileSize=100 MB, MaxScanSize=
400 MB — mobile APKs over 25 MB came back as "INSTREAM size limit
exceeded" from the scanner, which the service wrapped in a 502 JSON
body, which Caddy sometimes replaced with its own HTML error page under
flaky mobile transport. The browser then saw 'Unexpected token <' and
told the user 'Network error'.
Overlay a minimal clamd.conf (mirrors the image default plus the three
raised limits, all pinned at 2 GiB = 2147483648 bytes) via a read-only
bind mount. Rebuild not needed — only clamav restarts.
