chore(deps): update dependencies and remove unused files

Updated several dependencies including:
- @aws-sdk/client-s3 from 3.965.0 to 3.975.0
- @aws-sdk/client-ses from 3.965.0 to 3.975.0
- @aws-sdk/client-sqs from 3.965.0 to 3.975.0
- dotenv from ^16.6.1 to ^16.5.0
- form-data from ^4.0.2 to ^4.0.5
- typescript from 5.9.3 to 5.8.3

Removed unused files:
- backend/.yarn/releases/yarn-4.9.1.cjs
- backend/package-lock.json

backend/package.json

@@ -51,21 +51,18 @@
     "bcrypt": "^6.0.0",
     "class-transformer": "^0.5.1",
     "class-validator": "^0.14.2",
-    "cookie-parser": "^1.4.7",
     "date-fns": "^4.1.0",
     "date-fns-tz": "^3.2.0",
     "decimal.js": "^10.5.0",
     "docxtemplater": "^3.63.2",
-    "dotenv": "^16.6.1",
+    "dotenv": "^16.5.0",
     "exceljs": "^4.4.0",
     "express": "^5.1.0",
-    "express-rate-limit": "^8.2.1",
     "form-data": "^4.0.2",
     "generate-password": "^1.7.1",
     "googleapis": "^149.0.0",
     "handlebars": "^4.7.8",
     "heapdump": "^0.3.15",
-    "helmet": "^8.1.0",
     "html-to-text": "^9.0.5",
     "iconv-lite": "^0.6.3",
     "imap-simple": "^5.1.0",
@@ -109,7 +106,6 @@
     "@swc/core": "^1.11.29",
     "@total-typescript/ts-reset": "^0.6.1",
     "@types/bcrypt": "^5.0.2",
-    "@types/cookie-parser": "^1",
     "@types/express": "^5.0.2",
     "@types/heapdump": "^0",
     "@types/html-to-text": "^9.0.4",