Clarify direct precompile timeout contract

docs/setup.md

@@ -312,6 +312,12 @@ workers continue to use `/etc/uce/settings.cfg`. The parallel precompile
 regression uses private roots so a running proactive compiler cannot consume
 or publish its controlled race fixtures.
 
+Direct `--precompile` is a listener-free whole-generation gate, not a
+single-unit readiness probe. It scans the configured source root, waits for
+unit publication locks, and has no internal wall-clock timeout. Automation
+must wrap it in a finite external timeout, as the managed restart does, before
+starting separately deadline-bounded CLI or HTTP invocations.
+
 Prefer the managed restart when the service runs as an unprivileged user: it
 precompiles as that same user. Request-time publication still accepts readable
 artifacts produced by a trusted administrator. When Linux protected-hardlink