Let the setuid search run to its 15-minute bound, ask pacman once, and call a walk with errors incomplete

The search kept a two-minute limit of its own inside its 15-minute bound, so
a long walk always ended incomplete; pacman was asked once per path; and find
exiting with an error but some output was read as a complete walk. The bound
and the not-judged reasons move to the public rootsearch package so the
controller reads the same values (the review of 2026-10-09).

rootsearch/rootsearch.go

@@ -0,0 +1,19 @@
+// Package rootsearch holds what the node-engine's search for setuid programs and the controller that reads its
+// verdicts must agree on (novox/hq ADR 0266): how long one search may run, and the words a verdict starts with
+// while it has no answer. Public, so the controller imports these rather than keeps copies that could drift.
+package rootsearch
+
+import "time"
+
+// Bound is how long one search for setuid programs may run. It governs the whole search, the walk and the
+// package manager's answers together; the controller does not raise an agent account as not judged while the
+// first search after a start is within it.
+const Bound = 15 * time.Minute
+
+// The reasons of a root verdict the search could not answer yet.
+const (
+	// ReasonPending starts the reason while the first search since the engine started runs.
+	ReasonPending = "not judged yet (search running)"
+	// ReasonIncomplete starts the reason when no search has finished: one failed or ran out its bound.
+	ReasonIncomplete = "not judged (search incomplete)"
+)