Mirror the LLM_ENABLED wiring for OWN_DEVELOPER_IDS (own-portfolio
cannibalization, #1169): forward vars.OWN_DEVELOPER_IDS into the SSH deploy
(env block + envs list) and write it to backend/.env.runtime ONLY when
non-empty (conditional, like OPENAI_API_KEY/LLM_ENABLED). Non-sensitive
(public companyGroup ids) → actions variable. Unset → cannibalization keeps
the proxy (dormant). No literal id in the workflow (refs only).
Captures in the pipeline the value already set live on prod via .env.runtime
(OWN_DEVELOPER_IDS=6208 = PRINZIP, verified against domrf_kn → 28 projects).
Owner must set Forgejo Variable OWN_DEVELOPER_IDS=6208 for full pipeline
management; meanwhile the .env.runtime line holds (survives git reset).
Refs #1169
