fix: resolve all golangci-lint issues

Fixes #32

Changes:
- middleware.go: use max() builtin, strconv.Itoa, fix wsl whitespace
- database.go: fix nlreturn, noinlineerr, wsl whitespace
- handlers.go: remove unnecessary template.HTML conversion, unused import
- app.go: extract cleanupContainer to fix nestif, fix lll
- client.go: break long string literals to fix lll
- deploy.go: fix wsl whitespace
- auth_test.go: extract helpers to fix funlen, fix wsl/nlreturn/testifylint
- handlers_test.go: deduplicate IDOR tests, fix paralleltest
- validation_test.go: add parallel, fix funlen/wsl, nolint testpackage
- port_validation_test.go: add parallel, nolint testpackage
- ratelimit_test.go: add parallel where safe, nolint testpackage/paralleltest
- realip_test.go: add parallel, use NewRequestWithContext, fix wsl/funlen
- user.go: (noinlineerr already fixed by database.go pattern)

internal/service/auth/auth_test.go

@@ -71,71 +71,80 @@ func setupTestService(t *testing.T) (*auth.Service, func()) {
 	return svc, cleanup
 }
 
+func setupAuthService(t *testing.T, debug bool) *auth.Service {
+	t.Helper()
+
+	tmpDir := t.TempDir()
+
+	globals.SetAppname("upaas-test")
+	globals.SetVersion("test")
+
+	globalsInst, err := globals.New(fx.Lifecycle(nil))
+	require.NoError(t, err)
+
+	loggerInst, err := logger.New(
+		fx.Lifecycle(nil),
+		logger.Params{Globals: globalsInst},
+	)
+	require.NoError(t, err)
+
+	cfg := &config.Config{
+		Port:          8080,
+		DataDir:       tmpDir,
+		SessionSecret: "test-secret-key-at-least-32-chars",
+		Debug:         debug,
+	}
+
+	dbInst, err := database.New(fx.Lifecycle(nil), database.Params{
+		Logger: loggerInst,
+		Config: cfg,
+	})
+	require.NoError(t, err)
+
+	svc, err := auth.New(fx.Lifecycle(nil), auth.ServiceParams{
+		Logger:   loggerInst,
+		Config:   cfg,
+		Database: dbInst,
+	})
+	require.NoError(t, err)
+
+	return svc
+}
+
+func getSessionCookie(t *testing.T, svc *auth.Service) *http.Cookie {
+	t.Helper()
+
+	_, err := svc.CreateUser(context.Background(), "admin", "password123")
+	require.NoError(t, err)
+
+	user, err := svc.Authenticate(context.Background(), "admin", "password123")
+	require.NoError(t, err)
+
+	recorder := httptest.NewRecorder()
+	request := httptest.NewRequest(http.MethodGet, "/", nil)
+
+	err = svc.CreateSession(recorder, request, user)
+	require.NoError(t, err)
+
+	for _, c := range recorder.Result().Cookies() {
+		if c.Name == "upaas_session" {
+			return c
+		}
+	}
+
+	return nil
+}
+
 func TestSessionCookieSecureFlag(testingT *testing.T) {
 	testingT.Parallel()
 
 	testingT.Run("secure flag is true when debug is false", func(t *testing.T) {
 		t.Parallel()
 
-		tmpDir := t.TempDir()
-
-		globals.SetAppname("upaas-test")
-		globals.SetVersion("test")
-
-		globalsInst, err := globals.New(fx.Lifecycle(nil))
-		require.NoError(t, err)
-
-		loggerInst, err := logger.New(
-			fx.Lifecycle(nil),
-			logger.Params{Globals: globalsInst},
-		)
-		require.NoError(t, err)
-
-		cfg := &config.Config{
-			Port:          8080,
-			DataDir:       tmpDir,
-			SessionSecret: "test-secret-key-at-least-32-chars",
-			Debug:         false,
-		}
-
-		dbInst, err := database.New(fx.Lifecycle(nil), database.Params{
-			Logger: loggerInst,
-			Config: cfg,
-		})
-		require.NoError(t, err)
-
-		svc, err := auth.New(fx.Lifecycle(nil), auth.ServiceParams{
-			Logger:   loggerInst,
-			Config:   cfg,
-			Database: dbInst,
-		})
-		require.NoError(t, err)
-
-		// Create user and session, check cookie has Secure flag
-		_, err = svc.CreateUser(context.Background(), "admin", "password123")
-		require.NoError(t, err)
-
-		user, err := svc.Authenticate(context.Background(), "admin", "password123")
-		require.NoError(t, err)
-
-		recorder := httptest.NewRecorder()
-		request := httptest.NewRequest(http.MethodGet, "/", nil)
-
-		err = svc.CreateSession(recorder, request, user)
-		require.NoError(t, err)
-
-		cookies := recorder.Result().Cookies()
-		require.NotEmpty(t, cookies)
-
-		var sessionCookie *http.Cookie
-		for _, c := range cookies {
-			if c.Name == "upaas_session" {
-				sessionCookie = c
-				break
-			}
-		}
-		require.NotNil(t, sessionCookie, "session cookie should exist")
-		assert.True(t, sessionCookie.Secure, "session cookie should have Secure flag in production mode")
+		svc := setupAuthService(t, false)
+		cookie := getSessionCookie(t, svc)
+		require.NotNil(t, cookie, "session cookie should exist")
+		assert.True(t, cookie.Secure, "session cookie should have Secure flag in production mode")
 	})
 }
 
@@ -302,12 +311,14 @@ func TestCreateUserRaceCondition(testingT *testing.T) {
 		close(start)
 
 		var successes, failures int
+
 		for range goroutines {
 			err := <-results
 			if err == nil {
 				successes++
 			} else {
-				assert.ErrorIs(t, err, auth.ErrUserExists)
+				require.ErrorIs(t, err, auth.ErrUserExists)
+
 				failures++
 			}
 		}

internal/service/deploy/deploy.go

@@ -89,6 +89,7 @@ func newDeploymentLogWriter(ctx context.Context, deployment *models.Deployment)
 		flushCtx:   ctx,
 	}
 	w.flushed.Add(1)
+
 	go w.runFlushLoop()
 
 	return w