fix(api): correct compile errors in builder Result return type

- Fix error_info field name: source -> context
- Update create_database() convenience function return type to match
  builder::build() Result<unique_ptr<>> signature

Author: kcenon

database/integrated/unified_database_system.cpp

@@ -902,7 +902,7 @@ kcenon::common::Result<std::unique_ptr<unified_database_system>> unified_databas
             return kcenon::common::error_info{
                 result.error().code,
                 "Failed to connect: " + result.error().message,
-                result.error().source
+                result.error().context
             };
         }
     }

database/integrated/unified_database_system.h

@@ -652,9 +652,9 @@ inline std::unique_ptr<unified_database_system> create_database() {
  * @brief Create a database with builder configuration
  * @param backend Database backend type
  * @param connection_string Connection string
- * @return Unique pointer to configured database system
+ * @return Result containing configured database system or error
  */
-inline std::unique_ptr<unified_database_system> create_database(
+inline kcenon::common::Result<std::unique_ptr<unified_database_system>> create_database(
     backend_type backend,
     const std::string& connection_string) {