M2: POST /coach route wiring the planning coach

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

internal/web/web_test.go

@@ -1,12 +1,15 @@
 package web
 
 import (
+	"context"
 	"net/http"
 	"net/http/httptest"
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
+	"antidrift/internal/ai"
 	"antidrift/internal/domain"
 	"antidrift/internal/evidence"
 	"antidrift/internal/session"
@@ -98,3 +101,60 @@ func TestLockedStateHasNullEvidence(t *testing.T) {
 		t.Fatalf("locked payload should have null evidence: %s", js)
 	}
 }
+
+type stubCoach struct {
+	prop ai.Proposal
+	err  error
+}
+
+func (s stubCoach) Coach(ctx context.Context, intent string) (ai.Proposal, error) {
+	return s.prop, s.err
+}
+
+func TestCoachRouteHappyPath(t *testing.T) {
+	s := newTestServer(t)
+	s.ctrl.SetCoach(stubCoach{prop: ai.Proposal{NextAction: "Do X", SuccessCondition: "done", TimeboxSecs: 1500}})
+	r := s.Router()
+	_ = post(t, r, "/planning", "")
+	if w := post(t, r, "/coach", `{"intent":"do something"}`); w.Code != http.StatusOK {
+		t.Fatalf("/coach code %d body %s", w.Code, w.Body.String())
+	}
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if cv := s.ctrl.State().Coach; cv != nil && cv.Status == "ready" {
+			return
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+	t.Fatalf("coach never reached ready: %+v", s.ctrl.State().Coach)
+}
+
+func TestCoachRouteOutsidePlanning(t *testing.T) {
+	s := newTestServer(t)
+	s.ctrl.SetCoach(stubCoach{})
+	r := s.Router()
+	if w := post(t, r, "/coach", `{"intent":"x"}`); w.Code != http.StatusBadRequest {
+		t.Fatalf("expected 400, got %d", w.Code)
+	}
+}
+
+func TestCoachRouteInvalidJSON(t *testing.T) {
+	s := newTestServer(t)
+	r := s.Router()
+	_ = post(t, r, "/planning", "")
+	if w := post(t, r, "/coach", `not json`); w.Code != http.StatusBadRequest {
+		t.Fatalf("expected 400, got %d", w.Code)
+	}
+}
+
+func TestCoachRouteUnavailableDegrades(t *testing.T) {
+	s := newTestServer(t) // no SetCoach
+	r := s.Router()
+	_ = post(t, r, "/planning", "")
+	if w := post(t, r, "/coach", `{"intent":"x"}`); w.Code != http.StatusOK {
+		t.Fatalf("unavailable coach should still 200, got %d", w.Code)
+	}
+	if cv := s.ctrl.State().Coach; cv == nil || cv.Status != "error" {
+		t.Fatalf("want error status, got %+v", cv)
+	}
+}