modernize the codebase

Run the modernize linter across the codebase.
Change generated by running:

```
go run golang.org/x/tools/gopls/internal/analysis/modernize/cmd/modernize@latest -fix -test ./...
```

Ref:
https://pkg.go.dev/golang.org/x/tools/gopls/internal/analysis/modernize

internal/auth/jwt.go

@@ -2,6 +2,7 @@ package auth
 
 import (
 	"CatsOfMastodonBotGo/internal/config"
+	"maps"
 	"strings"
 	"time"
 
@@ -17,16 +18,14 @@ func NewJwtTokenGenerator(cfg *config.Config) *JwtTokenGenerator {
 	return &JwtTokenGenerator{cfg: cfg}
 }
 
-func (j *JwtTokenGenerator) GenerateToken(claims map[string]interface{}) (string, error) {
+func (j *JwtTokenGenerator) GenerateToken(claims map[string]any) (string, error) {
 	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
 		"exp": time.Now().AddDate(0, 0, 1).Unix(),
 		"iat": time.Now().Unix(),
 		"iss": j.cfg.JwtIssuer,
 		"aud": j.cfg.JwtAudience,
 	})
-	for k, v := range claims {
-		token.Claims.(jwt.MapClaims)[k] = v
-	}
+	maps.Copy(token.Claims.(jwt.MapClaims), claims)
 
 	return token.SignedString([]byte(j.cfg.JwtSecret))
 }
@@ -41,7 +40,7 @@ func (j *JwtTokenGenerator) GinMiddleware() gin.HandlerFunc {
 		}
 
 		tokenString := strings.TrimPrefix(authHeader, "Bearer ")
-		t, err := jwt.Parse(tokenString, func(t *jwt.Token) (interface{}, error) {
+		t, err := jwt.Parse(tokenString, func(t *jwt.Token) (any, error) {
 			if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
 				return nil, jwt.ErrSignatureInvalid
 			}
@@ -61,4 +60,4 @@ func (j *JwtTokenGenerator) GinMiddleware() gin.HandlerFunc {
 
 		c.Next()
 	}
-}
+}

internal/services/postService.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math/rand"
 	"net/http"
+	"slices"
 	"strings"
 
 	"gorm.io/gorm"
@@ -163,10 +164,5 @@ func (ps *PostService) GetMedia() domain.MediaAttachment {
 }
 
 func arrayContains(arr []string, str string) bool {
-	for _, a := range arr {
-		if a == str {
-			return true
-		}
-	}
-	return false
-}
+	return slices.Contains(arr, str)
+}

internal/web/handlers/adminDash.go

@@ -28,7 +28,7 @@ func NewAdminDashboardHandler(
 		postService: postService,
 		jwt:         jwt,
 		cfg:         cfg,
-		 imgKit:      imgKit,
+		imgKit:      imgKit,
 	}
 }
 
@@ -61,8 +61,8 @@ func (adh *AdminDashboardHandler) RejectMedia(c *gin.Context) {
 func (adh *AdminDashboardHandler) GetMedia(c *gin.Context) {
 	media := adh.postService.GetMedia()
 	// TODO: Fix this - we need to inject ImgKitHelper
-	 media.PreviewUrl = adh.imgKit.GetPreviewUrl(media.RemoteUrl)
-	 media.RemoteUrl = adh.imgKit.GetRemoteUrl(media.RemoteUrl)
+	media.PreviewUrl = adh.imgKit.GetPreviewUrl(media.RemoteUrl)
+	media.RemoteUrl = adh.imgKit.GetRemoteUrl(media.RemoteUrl)
 	c.JSON(http.StatusOK, media)
 }
 
@@ -77,7 +77,7 @@ func (adh *AdminDashboardHandler) Login(c *gin.Context) {
 	}
 
 	if input.Password == adh.cfg.AdminPassword { // Its more than enough for this project
-		token, err := adh.jwt.GenerateToken(map[string]interface{}{"role": "admin"})
+		token, err := adh.jwt.GenerateToken(map[string]any{"role": "admin"})
 		if err != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{"error": "Token generation failed"})
 			return
@@ -97,4 +97,4 @@ func (adh *AdminDashboardHandler) Login(c *gin.Context) {
 // Expose the JWT middleware for use in routes
 func (adh *AdminDashboardHandler) JWTMiddleware() gin.HandlerFunc {
 	return adh.jwt.GinMiddleware()
-}
+}

internal/web/handlers/oauth.go

@@ -10,9 +10,9 @@ import (
 )
 
 type OauthLoginHandler struct {
-	jwt         *auth.JwtTokenGenerator
+	jwt          *auth.JwtTokenGenerator
 	oauthHandler *auth.GiteaOAuth2Handler
-	cfg         *config.Config
+	cfg          *config.Config
 }
 
 func NewOauthLoginHandler(
@@ -55,7 +55,7 @@ func (olh *OauthLoginHandler) LoginWithGitea(c *gin.Context) {
 	// Check if the user's email is in the allowed list
 	for _, email := range olh.cfg.GiteaOauthAllowedEmails {
 		if email == userEmail {
-			token, err := olh.jwt.GenerateToken(map[string]interface{}{"role": "admin"})
+			token, err := olh.jwt.GenerateToken(map[string]any{"role": "admin"})
 			if err != nil {
 				c.JSON(http.StatusInternalServerError, gin.H{"error": "Token generation failed"})
 				return
@@ -70,4 +70,4 @@ func (olh *OauthLoginHandler) LoginWithGitea(c *gin.Context) {
 	c.JSON(401, gin.H{
 		"error": "oauth login failed or your email does not have access",
 	})
-}
+}