refactor: reorganize struct fields, add new handlers and storage backends

- [x] Reorder struct fields across codebase for consistency
- [x] Add analytics event handlers and tests
- [x] Add authentication API key management handlers and tests
- [x] Add pre-warming control handlers and tests
- [x] Implement S3 storage backend with tests
- [x] Implement SMB/CIFS storage backend with tests
- [x] Add CDN middleware tests
- [x] Integrate analytics tracking into cache manager
- [x] Add S3 and SMB storage initialization in app setup
- [x] Add CDN caching to proxy handlers
- [x] Remove distributed locking (Redis lock manager)
- [x] Remove proxy common package and utilities
- [x] Remove standalone HTTP server package
- [x] Remove logger middleware
- [x] Simplify error handling utilities
- [x] Update config with S3 and SMB options
- [x] Update cache manager signature to include analytics

pkg/app/handlers_prewarming_test.go

@@ -0,0 +1,162 @@
+package app
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gofiber/fiber/v2"
+	"github.com/lukaszraczylo/gohoarder/pkg/prewarming"
+	"github.com/stretchr/testify/suite"
+)
+
+type PrewarmingHandlersTestSuite struct {
+	suite.Suite
+	app           *fiber.App
+	appInst       *App
+	prewarmWorker *prewarming.Worker
+}
+
+func (s *PrewarmingHandlersTestSuite) SetupTest() {
+	// Create pre-warming worker (disabled by default)
+	s.prewarmWorker = prewarming.NewWorker(prewarming.Config{
+		Enabled:       false,
+		MaxConcurrent: 5,
+	})
+
+	// Create app instance
+	s.appInst = &App{
+		prewarmWorker: s.prewarmWorker,
+	}
+
+	// Create Fiber app
+	s.app = fiber.New()
+
+	// Register routes
+	s.app.Get("/api/admin/prewarming/status", s.appInst.handlePrewarmingStatus)
+	s.app.Post("/api/admin/prewarming/trigger", s.appInst.handlePrewarmingTrigger)
+	s.app.Post("/api/admin/prewarming/package", s.appInst.handlePrewarmingPackage)
+}
+
+func (s *PrewarmingHandlersTestSuite) TearDownTest() {
+	if s.prewarmWorker != nil {
+		s.prewarmWorker.Stop()
+	}
+}
+
+func TestPrewarmingHandlersTestSuite(t *testing.T) {
+	suite.Run(t, new(PrewarmingHandlersTestSuite))
+}
+
+func (s *PrewarmingHandlersTestSuite) TestHandlePrewarmingStatus() {
+	req := httptest.NewRequest("GET", "/api/admin/prewarming/status", nil)
+	resp, err := s.app.Test(req)
+	s.Require().NoError(err)
+	s.Equal(200, resp.StatusCode)
+
+	var result struct {
+		Enabled       bool `json:"enabled"`
+		Running       bool `json:"running"`
+		QueueSize     int  `json:"queue_size"`
+		ActiveWorkers int  `json:"active_workers"`
+	}
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	s.NoError(err)
+	s.False(result.Enabled) // Disabled in test setup
+}
+
+func (s *PrewarmingHandlersTestSuite) TestHandlePrewarmingTrigger() {
+	req := httptest.NewRequest("POST", "/api/admin/prewarming/trigger", nil)
+	resp, err := s.app.Test(req)
+	s.Require().NoError(err)
+	s.Equal(200, resp.StatusCode)
+
+	var result map[string]interface{}
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	s.NoError(err)
+	s.Contains(result, "message")
+}
+
+func (s *PrewarmingHandlersTestSuite) TestHandlePrewarmingPackage() {
+	tests := []struct {
+		requestBody    map[string]string
+		name           string
+		expectedStatus int
+	}{
+		{
+			name: "prewarm npm package",
+			requestBody: map[string]string{
+				"registry": "npm",
+				"name":     "lodash",
+				"version":  "4.17.21",
+			},
+			expectedStatus: 200,
+		},
+		{
+			name: "prewarm pypi package",
+			requestBody: map[string]string{
+				"registry": "pypi",
+				"name":     "requests",
+				"version":  "2.28.0",
+			},
+			expectedStatus: 200,
+		},
+		{
+			name: "prewarm go package",
+			requestBody: map[string]string{
+				"registry": "go",
+				"name":     "github.com/stretchr/testify",
+				"version":  "v1.8.0",
+			},
+			expectedStatus: 200,
+		},
+		{
+			name: "missing registry",
+			requestBody: map[string]string{
+				"name":    "lodash",
+				"version": "4.17.21",
+			},
+			expectedStatus: 400,
+		},
+		{
+			name: "missing name",
+			requestBody: map[string]string{
+				"registry": "npm",
+				"version":  "4.17.21",
+			},
+			expectedStatus: 400,
+		},
+		{
+			name: "missing version",
+			requestBody: map[string]string{
+				"registry": "npm",
+				"name":     "lodash",
+			},
+			expectedStatus: 400,
+		},
+	}
+
+	for _, tt := range tests {
+		s.Run(tt.name, func() {
+			bodyBytes, err := json.Marshal(tt.requestBody)
+			s.Require().NoError(err)
+
+			req := httptest.NewRequest("POST", "/api/admin/prewarming/package", bytes.NewReader(bodyBytes))
+			req.Header.Set("Content-Type", "application/json")
+
+			resp, err := s.app.Test(req)
+			s.Require().NoError(err)
+			s.Equal(tt.expectedStatus, resp.StatusCode)
+		})
+	}
+}
+
+func (s *PrewarmingHandlersTestSuite) TestHandlePrewarmingPackageInvalidJSON() {
+	req := httptest.NewRequest("POST", "/api/admin/prewarming/package", bytes.NewReader([]byte("invalid json")))
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := s.app.Test(req)
+	s.Require().NoError(err)
+	s.Equal(400, resp.StatusCode)
+}