feat: Implementa gestione intelligente della chiave sorgente con rilevamento PK

- Aggiunge rilevamento automatico Primary Key per connessioni database
- Rimuove completamente il fallback automatico per lato sorgente
- Implementa selezione manuale obbligatoria per file e sorgenti non-DB
- Migliora UI con suggerimenti intelligenti e feedback visivo
- Aggiunge validazione multi-livello (UI, pre-transfer, runtime)
- Introduce metodo GetPrimaryKeyFieldAsync in IDatabaseManager
- Modifica GenerateSourceKey per richiedere sempre campo specifico
- Implementa controllo IsTransferButtonEnabled per validazione form

Breaking changes:
- La generazione automatica delle chiavi sorgente è stata rimossa
- Il campo chiave sorgente è ora obbligatorio quando si usa il sistema associazioni

Fixes: Risolve problema di discovery schema vuoto con selezione database

DataConnection/REST/Interfaces/IRestServiceClient.cs

@@ -42,9 +42,7 @@ namespace DataConnection.REST.Interfaces
         /// <param name="entityData">The data for the new entity as key-value pairs.</param>
         /// <param name="cancellationToken">Cancellation token.</param>
         /// <returns>The created entity data or null if creation failed.</returns>
-        Task<Dictionary<string, object>?> CreateEntityAsync(string entityName, Dictionary<string, object> entityData, CancellationToken cancellationToken = default);
-
-        /// <summary>
+        Task<Dictionary<string, object>?> CreateEntityAsync(string entityName, Dictionary<string, object> entityData, CancellationToken cancellationToken = default);        /// <summary>
         /// Creates a new entity or updates an existing one (upsert operation).
         /// </summary>
         /// <param name="entityName">The name of the entity to upsert.</param>
@@ -53,6 +51,41 @@ namespace DataConnection.REST.Interfaces
         /// <returns>The upserted entity data or null if operation failed.</returns>
         Task<Dictionary<string, object>?> UpsertEntityAsync(string entityName, Dictionary<string, object> entityData, CancellationToken cancellationToken = default);
 
+        /// <summary>
+        /// Searches for entities matching the specified key fields.
+        /// </summary>
+        /// <param name="entityName">The name of the entity to search.</param>
+        /// <param name="keyFields">The key fields and their values to search for.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>A list of matching entities.</returns>
+        Task<List<Dictionary<string, object>>> FindEntitiesByKeysAsync(string entityName, Dictionary<string, object> keyFields, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// Deletes an entity by its ID or unique identifier.
+        /// </summary>
+        /// <param name="entityName">The name of the entity to delete.</param>
+        /// <param name="entityId">The ID or unique identifier of the entity to delete.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>True if deletion was successful, false otherwise.</returns>
+        Task<bool> DeleteEntityAsync(string entityName, string entityId, CancellationToken cancellationToken = default);        /// <summary>
+        /// Updates an existing entity by its ID with the provided data.
+        /// </summary>
+        /// <param name="entityName">The name of the entity to update.</param>
+        /// <param name="entityId">The ID or unique identifier of the entity to update.</param>
+        /// <param name="entityData">The data to update as key-value pairs.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>The updated entity data or null if update failed.</returns>
+        Task<Dictionary<string, object>?> UpdateEntityAsync(string entityName, string entityId, Dictionary<string, object> entityData, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// Searches for entities matching the specified required fields to detect duplicates.
+        /// </summary>
+        /// <param name="entityName">The name of the entity to search.</param>
+        /// <param name="requiredFields">The required fields and their values to search for.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>A list of matching entities.</returns>
+        Task<List<Dictionary<string, object>>> FindEntitiesByRequiredFieldsAsync(string entityName, Dictionary<string, object> requiredFields, CancellationToken cancellationToken = default);
+
         // Add other methods as needed (PUT, DELETE, PATCH, etc.)
         // Consider adding methods for handling raw HttpResponseMessage or string responses
     }