Remove /knowledge/path; folded into /settings

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

internal/web/web_test.go

@@ -14,6 +14,7 @@ import (
 	"antidrift/internal/evidence"
 	"antidrift/internal/knowledge"
 	"antidrift/internal/session"
+	"antidrift/internal/settings"
 	"antidrift/internal/tasks"
 
 	"github.com/gin-gonic/gin"
@@ -398,12 +399,17 @@ func TestEnforceTogglePutsEnforcedOnTheWire(t *testing.T) {
 func TestKnowledgePathSelectionReloads(t *testing.T) {
 	s := newTestServer(t)
 	s.ctrl.SetKnowledge(stubSource{profile: knowledge.Profile{Path: "/default"}})
+	s.SetSettings(filepath.Join(t.TempDir(), "settings.json"),
+		settings.Settings{}, func(ss settings.Settings) error {
+			s.ctrl.SetKnowledgePath(ss.KnowledgePath)
+			return nil
+		})
 	r := s.Router()
 	if w := post(t, r, "/planning", ""); w.Code != http.StatusOK {
 		t.Fatalf("/planning code %d", w.Code)
 	}
-	if w := post(t, r, "/knowledge/path", `{"path":"/custom/profile.md"}`); w.Code != http.StatusOK {
-		t.Fatalf("/knowledge/path code %d body %s", w.Code, w.Body.String())
+	if w := post(t, r, "/settings", `{"ai_backend":"claude","marvin_cmd":"","knowledge_path":"/custom/profile.md"}`); w.Code != http.StatusOK {
+		t.Fatalf("/settings code %d body %s", w.Code, w.Body.String())
 	}
 	deadline := time.Now().Add(2 * time.Second)
 	for time.Now().Before(deadline) {