release: add docs/SERVING.md

docs/SERVING.md

@@ -590,7 +590,7 @@ available?", which is exactly the kind of drift the project's discipline forbids
    it if it exits. See §9.
 5. **Environment** — exports `SATQUERY_DEVICE=cpu`, `SATQUERY_ASSET_ENABLED=1`,
    `SATQUERY_ASSET_DIR=/tmp/satquery-assets`, and
-   `SATQUERY_HUB_URL=https://satquery-backend-m4yv.onrender.com`.
+   `SATQUERY_HUB_URL=https://<backend-host>`.
 6. **Verification** — step 3 verifies the agent "announced to hub", so the launcher does not report
    success merely because the process started.
 
@@ -973,7 +973,7 @@ The agent's role, assembled from the evidence that exists:
   announcing is part of the agent's contract and the launcher treats a failed announcement as a failed
   launch.
 - **`SATQUERY_HUB_URL` names the hub.** The launcher sets it to
-  `https://satquery-backend-m4yv.onrender.com`, which is the same host the frontend's
+  `https://<backend-host>`, which is the same host the frontend's
   `<meta name="satquery-api-base">` names (`frontend/mission.html`). So the hub, the orchestrator, and
   the API base are one host.
 - **It is supervised, and it is started after the service.** The launcher starts the service