Add web server, SSE handlers, and UI

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

internal/web/web_test.go

@@ -0,0 +1,71 @@
+package web
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"antidrift/internal/domain"
+	"antidrift/internal/session"
+
+	"github.com/gin-gonic/gin"
+)
+
+func newTestServer(t *testing.T) *Server {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	path := filepath.Join(t.TempDir(), "state.json")
+	ctrl, err := session.New(path)
+	if err != nil {
+		t.Fatalf("controller: %v", err)
+	}
+	return NewServer(ctrl)
+}
+
+func post(t *testing.T, r http.Handler, path, body string) *httptest.ResponseRecorder {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(body))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+	return w
+}
+
+func TestPlanningThenCommitmentReachesActive(t *testing.T) {
+	s := newTestServer(t)
+	r := s.Router()
+
+	if w := post(t, r, "/planning", ""); w.Code != http.StatusOK {
+		t.Fatalf("/planning code %d", w.Code)
+	}
+	body := `{"next_action":"Build web","success_condition":"web tests pass","timebox_secs":1500}`
+	if w := post(t, r, "/commitment", body); w.Code != http.StatusOK {
+		t.Fatalf("/commitment code %d body %s", w.Code, w.Body.String())
+	}
+	if s.ctrl.State().RuntimeState != domain.RuntimeActive {
+		t.Fatalf("expected Active, got %s", s.ctrl.State().RuntimeState)
+	}
+}
+
+func TestCommitmentRejectsInvalidInput(t *testing.T) {
+	s := newTestServer(t)
+	r := s.Router()
+	_ = post(t, r, "/planning", "")
+	body := `{"next_action":"","success_condition":"x","timebox_secs":1500}`
+	w := post(t, r, "/commitment", body)
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("expected 400, got %d", w.Code)
+	}
+}
+
+func TestIllegalTransitionReturns409(t *testing.T) {
+	s := newTestServer(t)
+	r := s.Router()
+	// /complete from Locked is illegal.
+	w := post(t, r, "/complete", "")
+	if w.Code != http.StatusConflict {
+		t.Fatalf("expected 409, got %d", w.Code)
+	}
+}