Document that deploy_component waits for restart: true and reports restart_completed

reference/operations-api/operations.md

@@ -945,6 +945,18 @@ Response:
 }
 ```
 
+#### Restarting (`restart`)
+
+<VersionBadge type="changed" version="v5.3.0" />
+
+`"restart": true` restarts this node's HTTP worker threads and waits for that restart to finish before responding, so a successful response means every worker thread is serving the newly deployed code. Until a worker has been replaced it is still running the previous code, and on platforms where replacements share a listening port it keeps accepting connections for the whole rolling restart — before this, a client that treated the immediate response as "the component is live" could be served by a worker that had never loaded it.
+
+The wait follows the restart's own progress rather than a fixed timeout, so a wide thread pool, a slow component install, or a worker draining in-flight work does not cut it short. That also means the response can take as long as the install plus the restart — tens of seconds on a slow install with many worker threads — so a caller with a short request timeout should use `"restart": "rolling"` and poll its job instead. If it does give up — the restart stopped reporting progress, ran past the wait's absolute ceiling, or left a worker thread that could not be replaced — the restart continues in the background and the Harper log says which of those happened. A restart that fails does not fail the deploy: the component is already installed and replicated.
+
+`"restart": "rolling"` is unchanged: instead of restarting inline it starts a replicated `restart_service` job and returns its `restartJobId` to poll.
+
+`drop_component` accepts `"restart": true` and waits for the restart the same way (v5.3.0).
+
 ### Deployment Operations
 
 Harper records every `deploy_component` call in the `system.hdb_deployment` table, capturing the full lifecycle of a deployment including phase transitions (prepare → load → replicate → restart → success/failed), per-node outcomes, and a bounded event log of install output.