Switch contact form to self-hosted SMTP via nodemailer, remove formsubmit.co

package-lock.json

@@ -9,6 +9,7 @@
       "version": "0.0.0",
       "dependencies": {
         "express": "^5.2.1",
+        "nodemailer": "^8.0.5",
         "react": "^19.2.4",
         "react-dom": "^19.2.4",
         "react-markdown": "^10.1.0",
@@ -18,6 +19,7 @@
       "devDependencies": {
         "@eslint/js": "^9.39.4",
         "@types/node": "^24.12.0",
+        "@types/nodemailer": "^8.0.0",
         "@types/react": "^19.2.14",
         "@types/react-dom": "^19.2.3",
         "@vitejs/plugin-react": "^6.0.0",
@@ -939,6 +941,16 @@
         "undici-types": "~7.16.0"
       }
     },
+    "node_modules/@types/nodemailer": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/@types/nodemailer/-/nodemailer-8.0.0.tgz",
+      "integrity": "sha512-fyf8jWULsCo0d0BuoQ75i6IeoHs47qcqxWc7yUdUcV0pOZGjUTTOvwdG1PRXUDqN/8A64yQdQdnA2pZgcdi+cA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/react": {
       "version": "19.2.14",
       "resolved": "https://registry.npmjs.org/@types/react/-/react-19.2.14.tgz",
@@ -4129,6 +4141,15 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/nodemailer": {
+      "version": "8.0.5",
+      "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-8.0.5.tgz",
+      "integrity": "sha512-0PF8Yb1yZuQfQbq+5/pZJrtF6WQcjTd5/S4JOHs9PGFxuTqoB/icwuB44pOdURHJbRKX1PPoJZtY7R4VUoCC8w==",
+      "license": "MIT-0",
+      "engines": {
+        "node": ">=6.0.0"
+      }
+    },
     "node_modules/object-inspect": {
       "version": "1.13.4",
       "resolved": "https://registry.npmjs.org/object-inspect/-/object-inspect-1.13.4.tgz",