first commit of refactor

backend/domain/NormalizedTx.js

@@ -0,0 +1,19 @@
+/**
+ * NormalizedTx - Standardized transaction representation
+ * 
+ * Defines the minimal, normalized transaction data relevant
+ * for tracking blockchain activity. 
+ */
+
+/**
+ * @typedef {Object} NormalizedTx
+ * @property {string} hash - Transaction hash (0x prefixed)
+ * @property {string} from - Sender address (lowercase, 0x prefixed)
+ * @property {string|null} to - Recipient address (lowercase, 0x prefixed, null for contract creation)
+ * @property {string} value - Value transferred in Wei (as string to preserve precision)
+ * @property {number} blockNumber - Block number where transaction was included
+ * @property {number} blockTimestamp - Unix timestamp of the block
+ */
+
+export default {};
+