implement admin key authentication and refactor API key handling

internal/handlers/example.go

@@ -1,24 +0,0 @@
-package handlers
-
-import (
-	"encoding/json"
-	"io"
-	"net/http"
-)
-
-var ExampleGet http.HandlerFunc = func(w http.ResponseWriter, r *http.Request) {
-	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(map[string]string{"message": "example GET"})
-}
-
-var ExamplePost http.HandlerFunc = func(w http.ResponseWriter, r *http.Request) {
-	body, _ := io.ReadAll(r.Body)
-	defer r.Body.Close()
-
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(http.StatusCreated)
-	json.NewEncoder(w).Encode(map[string]any{
-		"message":  "example POST",
-		"received": string(body),
-	})
-}