Refactor: Implement uber-go/fx dependency injection

- Replace global variable pattern with proper dependency injection
- Add uber-go/fx for automatic dependency resolution
- Refactor all services and handlers to use constructor injection
- Eliminate fragile initialization order dependencies
- Improve testability and modularity
- Add structured logging with zap

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

internal/config/config.go

@@ -8,7 +8,7 @@ import (
 	"github.com/joho/godotenv"
 )
 
-type config struct {
+type Config struct {
 	AdminPassword string
 	Instance      string
 	Tag           string
@@ -26,15 +26,13 @@ type config struct {
 
 	ImageKitId string
 
-	GiteaOauthInstance	string
-	GiteaOauthClientID	string
-	GiteaOauthClientSecret	string
-	GiteaOauthAllowedEmails	[]string
+	GiteaOauthInstance      string
+	GiteaOauthClientID      string
+	GiteaOauthClientSecret  string
+	GiteaOauthAllowedEmails []string
 }
 
-var Config *config
-
-func Load() *config {
+func Load() *Config {
 	err := godotenv.Load()
 	if err != nil {
 		slog.Warn("Error loading .env file - Using environment variables instead")
@@ -104,8 +102,8 @@ func Load() *config {
 	if imageKitId == "" {
 		slog.Info("No imagekit id provided, not using imagekit.io")
 	}
-	// Inititlize AppContext
-	var appContext = &config{
+	// Initialize AppContext
+	return &Config{
 		AdminPassword: adminPassword,
 		Instance:      instance,
 		Tag:           tag,
@@ -123,15 +121,9 @@ func Load() *config {
 
 		ImageKitId: imageKitId,
 
-		GiteaOauthInstance:	giteaOauthInstance,
-		GiteaOauthClientID:	giteaOauthClientID,
-		GiteaOauthClientSecret:	giteaOauthClientSecret,
+		GiteaOauthInstance:      giteaOauthInstance,
+		GiteaOauthClientID:      giteaOauthClientID,
+		GiteaOauthClientSecret:  giteaOauthClientSecret,
 		GiteaOauthAllowedEmails: giteaOauthAllowedEmailsParsed,
 	}
-	return appContext
-
-}
-
-func Init() {
-	Config = Load()
-}
+}