add nodemailer integration for loan email notifications and implement loan info retrieval

backend/package-lock.json

@@ -14,7 +14,8 @@
         "ejs": "^3.1.10",
         "express": "^5.1.0",
         "jose": "^6.0.12",
-        "mysql2": "^3.14.3"
+        "mysql2": "^3.14.3",
+        "nodemailer": "^7.0.6"
       }
     },
     "node_modules/accepts": {
@@ -713,6 +714,15 @@
         "node": ">= 0.6"
       }
     },
+    "node_modules/nodemailer": {
+      "version": "7.0.6",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-7.0.6.tgz",
+      "integrity": "sha512-F44uVzgwo49xboqbFgBGkRaiMgtoBrBEWCVincJPK9+S9Adkzt/wXCLKbf7dxucmxfTI5gHGB+bEmdyzN6QKjw==",
+      "license": "MIT-0",
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/object-assign": {
       "version": "4.1.1",
       "resolved": "https://registry.npmjs.org/object-assign/-/object-assign-4.1.1.tgz",