Kestrel rejects the h2c upgrade preface; Caddy surfaced that as a 502 per
request while the backend answered 200 on plain HTTP/1.1 from Caddy's network.
Contrast recorded: Plex PMS needs the TLS transport, Jellyfin needs none.
All in-repo path references (AGENTS.md, README, old scripts, report artifacts,
test code paths) rewritten in the same commit; focused-test map extended for
.gitignore, old/scripts/*, dankclaw/comfyui/*, and report/* per this repo's
own convention ('add one before committing'). Obsidian wikilinks are
title-based and unaffected.