IPCR Forge: fixes from the holyhorse run

- forge-runner: 1G (act_runner was OOM-killed mid-job at 256M)
- bridge: log rad's stdout on failure; page links Gitea from its own host
  (html_url is the internal address); description fallback without it
- docs/forge.md: holyhorse verification and findings 11-14

forge/gitea.go

@@ -96,7 +96,6 @@ type repo struct {
 	Mirror        bool   `json:"mirror"`
 	Empty         bool   `json:"empty"`
 	DefaultBranch string `json:"default_branch"`
-	HTMLURL       string `json:"html_url"`
 	Owner         struct {
 		Login string `json:"login"`
 		// public | limited | private. Only a public owner's repositories are public.