chore: remove the unused base-64 dependency and list all providers in env.example (#881)

Keep the viewport settings so iOS Safari does not zoom on input focus.

package-lock.json

@@ -45,7 +45,6 @@
                 "@radix-ui/react-use-controllable-state": "^1.2.2",
                 "@xmldom/xmldom": "^0.9.8",
                 "ai": "^6.0.300",
-                "base-64": "^1.0.0",
                 "class-variance-authority": "^0.7.1",
                 "clsx": "^2.1.1",
                 "cmdk": "^1.1.1",
@@ -10053,12 +10052,6 @@
                 "node": "18 || 20 || >=22"
             }
         },
-        "node_modules/base-64": {
-            "version": "1.0.0",
-            "resolved": "https://registry.npmjs.org/base-64/-/base-64-1.0.0.tgz",
-            "integrity": "sha512-kwDPIFCGx0NZHog36dj+tHiwP4QMzsZ3AgMViUBKI0+V5n4U0ufTCUMhnQ04diaRI8EX/QcPfql7zlhZ7j4zgg==",
-            "license": "MIT"
-        },
         "node_modules/base64-js": {
             "version": "1.5.1",
             "resolved": "https://registry.npmjs.org/base64-js/-/base64-js-1.5.1.tgz",