feat: add admin billing system, SMTP email, rename to CloudLense

- Add payments, coupons, credits, invoices management to admin dashboard
- Add 7 new admin tabs: Overview, Users, Orgs, Payments, Coupons, Credits, Invoices
- Replace Resend with SMTP email via nodemailer (info@dk0.dev / mail.dk0.dev)
- Add professional branded email templates (alerts, welcome, invoice, credit, password reset)
- Add database migration for payments, coupons, coupon_redemptions, credit_transactions, invoices tables
- Add credit_balance column to organizations
- Add RLS policies for all new tables
- Add 4 new API routes: /api/admin/{payments,coupons,credits,invoices}
- Rename project from website-monitoring to CloudLense
- Update all package.json names and README

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/package-lock.json

@@ -28,6 +28,7 @@
         "lighthouse": "^12.6.1",
         "lucide-react": "^0.477.0",
         "next": "^15.2.4",
+        "nodemailer": "^8.0.1",
         "postcss": "^8.5.3",
         "puppeteer": "^24.7.0",
         "react": "^19.0.0",
@@ -48,6 +49,7 @@
         "@testing-library/jest-dom": "^6.6.3",
         "@testing-library/react": "^16.0.1",
         "@types/node": "^20",
+        "@types/nodemailer": "^7.0.11",
         "@types/react": "^19",
         "@types/react-dom": "^19",
         "concurrently": "^9.1.2",
@@ -3754,6 +3756,16 @@
         "undici-types": "~6.21.0"
       }
     },
+    "node_modules/@types/nodemailer": {
+      "version": "7.0.11",
+      "resolved": "https://registry.npmjs.org/@types/nodemailer/-/nodemailer-7.0.11.tgz",
+      "integrity": "sha512-E+U4RzR2dKrx+u3N4DlsmLaDC6mMZOM/TPROxA0UAPiTgI0y4CEFBmZE+coGWTjakDriRsXG368lNk1u9Q0a2g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/phoenix": {
       "version": "1.6.6",
       "resolved": "https://registry.npmjs.org/@types/phoenix/-/phoenix-1.6.6.tgz",
@@ -11705,6 +11717,15 @@
       "integrity": "sha512-xxOWJsBKtzAq7DY0J+DTzuz58K8e7sJbdgwkbMWQe8UYB6ekmsQ45q0M/tJDsGaZmbC+l7n57UV8Hl5tHxO9uw==",
       "license": "MIT"
     },
+    "node_modules/nodemailer": {
+      "version": "8.0.1",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-8.0.1.tgz",
+      "integrity": "sha512-5kcldIXmaEjZcHR6F28IKGSgpmZHaF1IXLWFTG+Xh3S+Cce4MiakLtWY+PlBU69fLbRa8HlaGIrC/QolUpHkhg==",
+      "license": "MIT-0",
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/normalize-path": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/normalize-path/-/normalize-path-3.0.0.tgz",