feat: email change UI, Swagger UI improvements, key recovery link on landing page

- Email change modal: API key + new email → verification code → confirmed
- Swagger UI with proper OpenAPI spec (public/openapi.json + swagger-ui assets)
- Key recovery link prominently on landing page hero section
- Footer link for email change
- Updated docs.html to use swagger-ui bundle

package-lock.json

@@ -15,7 +15,8 @@
         "nanoid": "^5.0.0",
         "nodemailer": "^8.0.1",
         "puppeteer": "^24.0.0",
-        "stripe": "^20.3.1"
+        "stripe": "^20.3.1",
+        "swagger-ui-dist": "^5.31.0"
       },
       "devDependencies": {
         "@types/express": "^5.0.0",
@@ -892,6 +893,12 @@
         "win32"
       ]
     },
+    "node_modules/@scarf/scarf": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@scarf/scarf/-/scarf-1.4.0.tgz",
+      "integrity": "sha512-xxeapPiUXdZAE3che6f3xogoJPeZgig6omHEy1rIY5WVsB3H2BHNnZH+gHG6x91SCWyQCzWGsuL2Hh3ClO5/qQ==",
+      "hasInstallScript": true
+    },
     "node_modules/@tootallnate/quickjs-emscripten": {
       "version": "0.23.0",
       "resolved": "https://registry.npmjs.org/@tootallnate/quickjs-emscripten/-/quickjs-emscripten-0.23.0.tgz",
@@ -3414,6 +3421,14 @@
         }
       }
     },
+    "node_modules/swagger-ui-dist": {
+      "version": "5.31.0",
+      "resolved": "https://registry.npmjs.org/swagger-ui-dist/-/swagger-ui-dist-5.31.0.tgz",
+      "integrity": "sha512-zSUTIck02fSga6rc0RZP3b7J7wgHXwLea8ZjgLA3Vgnb8QeOl3Wou2/j5QkzSGeoz6HusP/coYuJl33aQxQZpg==",
+      "dependencies": {
+        "@scarf/scarf": "=1.4.0"
+      }
+    },
     "node_modules/tar-fs": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/tar-fs/-/tar-fs-3.1.1.tgz",