mesh-issues: say in reserve's answer when hq could not be read, and grant the import its records calls (review of #204)

A number handed out unchecked against hq is a failure that must be loud, so
the answer carries a warning, not only the log. The import already calls
records_status and records_read; invokes now names them.

modules/mesh-issues/README.md

@@ -209,7 +209,8 @@ sessions writing a record at once never take one number.
   reserve of a kind is refused and nothing is spent.
 - **Never at or below a number hq holds**: each reserve reads hq again, and a counter that stands below the
   highest number there (one taken by hand) is raised to it first, written only at the revision read. When
-  hq cannot be read once the counter has started, the counter is used as it stands.
+  hq cannot be read once the counter has started, the counter is used as it stands, and the answer's
+  `warning` says the number was not checked against hq.
 - **Open branches are the floor's job.** The tracker reads hq's checkout of `main` and cannot list a folder on
   another branch with the forge tools it may call; a number taken on an open branch and not yet merged is
   covered by the floor. Before the first reserve of a kind, the operator raises `decision-floor` or