Wire the semantic nudge into the daemon and document M3.5

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -23,6 +23,15 @@ go test ./...
 
 ## Status
 
+M3.5 (semantic nudge): the drift interceptor catches the *wrong app*, but not
+the *wrong work inside a right app*. M3.5 adds a third, ambient AI role that —
+only while you are on-task in an allowed app — periodically reads your recent
+window titles and, if the trajectory has wandered from the commitment, shows a
+soft, dismissible "Heads up" line (no interrupt, no buttons to fight). It is
+debounced to roughly one check every five minutes, reuses the same CLI backend
+as the coach and drift judge, and degrades gracefully — without it, everything
+else still works.
+
 M3 (drift interceptor): while a commitment is Active, the daemon watches the
 focused window. A cheap local match against the session's allowed window classes
 is authoritative for on-task; only unmatched windows are sent to the LLM drift

cmd/antidriftd/main.go

@@ -41,7 +41,8 @@ func main() {
 		svc := ai.NewService(backend)
 		ctrl.SetCoach(svc)
 		ctrl.SetDriftJudge(svc)
-		log.Printf("ai: %s backend (coach + drift judge)", backend.Name())
+		ctrl.SetNudge(svc)
+		log.Printf("ai: %s backend (coach + drift judge + nudge)", backend.Name())
 	}
 
 	src := evidence.NewSource()