fix(tests): handle all Close() and Decode() errors across integration tests

Replace all unhandled resp.Body.Close() calls throughout the test suite:

- Deferred calls: replace 'defer VAR.Body.Close()' with a closure that explicitly
  discards the error via 'defer func(Body io.ReadCloser) { _ = Body.Close() }(VAR.Body)'
- Immediate calls: replace 'VAR.Body.Close()' with '_ = VAR.Body.Close()'

Replace all unhandled json.NewDecoder(VAR.Body).Decode(&x) calls with error capture
and require.NoError assertion. Files using httptest.ResponseRecorder (collections_preview,
processing_issues) use 'err :=' declaration; suite-style tests (scanner_integration,
dashboard_integration) use s.T() instead of t.

cmd/server/tests/websocket_test.go

@@ -6,6 +6,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -83,7 +84,9 @@ func TestWebSocketDeviceAuth(t *testing.T) {
 	require.NoError(t, err, "WebSocket connection with device token should succeed")
 	defer ws.Close()
 	if resp != nil {
-		defer resp.Body.Close()
+		defer func(Body io.ReadCloser) {
+			_ = Body.Close()
+		}(resp.Body)
 		require.Equal(t, http.StatusSwitchingProtocols, resp.StatusCode, "Should upgrade to WebSocket")
 	}
 	// Read initial state message
@@ -135,7 +138,9 @@ func TestWebSocketProgressBroadcast(t *testing.T) {
 	client := &http.Client{}
 	resp, err := client.Do(req)
 	require.NoError(t, err)
-	defer resp.Body.Close()
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
 
 	assert.Equal(t, http.StatusOK, resp.StatusCode)
 
@@ -253,11 +258,14 @@ func TestWebSocketUserScopedBroadcast(t *testing.T) {
 
 	collectionResp, err := client.Do(collectionHTTP)
 	require.NoError(t, err)
-	defer collectionResp.Body.Close()
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(collectionResp.Body)
 	require.Equal(t, http.StatusCreated, collectionResp.StatusCode)
 
 	var collectionResult map[string]interface{}
-	json.NewDecoder(collectionResp.Body).Decode(&collectionResult)
+	err = json.NewDecoder(collectionResp.Body).Decode(&collectionResult)
+	require.NoError(t, err)
 	collectionID := collectionResult["id"].(string)
 
 	// Create a test book via API
@@ -289,7 +297,9 @@ func TestWebSocketUserScopedBroadcast(t *testing.T) {
 
 	addResp, err := client.Do(addHTTP)
 	require.NoError(t, err)
-	defer addResp.Body.Close()
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(addResp.Body)
 	require.Equal(t, http.StatusNoContent, addResp.StatusCode)
 
 	// Admin should receive collection_updated message
@@ -313,7 +323,7 @@ func connectWebSocketToServer(t *testing.T, serverURL string, token string) *web
 	ws, resp, err := websocket.DefaultDialer.Dial(wsURL, nil)
 	require.NoError(t, err, "WebSocket connection should succeed")
 	if resp != nil {
-		resp.Body.Close()
+		_ = resp.Body.Close()
 	}
 	require.NotNil(t, ws, "WebSocket connection should be established")