feat: launch Gemini 3 in Gemini CLI 🚀🚀🚀 (in main) (#13287)

Co-authored-by: Adam Weidman <65992621+adamfweidman@users.noreply.github.com>
Co-authored-by: Sehoon Shon <sshon@google.com>
Co-authored-by: Adib234 <30782825+Adib234@users.noreply.github.com>
Co-authored-by: Sandy Tao <sandytao520@icloud.com>
Co-authored-by: Abhi <43648792+abhipatel12@users.noreply.github.com>
Co-authored-by: Aishanee Shah <aishaneeshah@gmail.com>
Co-authored-by: gemini-cli-robot <gemini-cli-robot@google.com>
Co-authored-by: Gal Zahavi <38544478+galz10@users.noreply.github.com>
Co-authored-by: Jacob Richman <jacob314@gmail.com>
Co-authored-by: joshualitt <joshualitt@google.com>
Co-authored-by: Jenna Inouye <jinouye@google.com>

schemas/settings.schema.json

@@ -23,6 +23,13 @@
       "default": {},
       "type": "object",
       "properties": {
+        "previewFeatures": {
+          "title": "Preview Features (e.g., models)",
+          "description": "Enable preview features (e.g., preview models).",
+          "markdownDescription": "Enable preview features (e.g., preview models).\n\n- Category: `General`\n- Requires restart: `yes`\n- Default: `false`",
+          "default": false,
+          "type": "boolean"
+        },
         "preferredEditor": {
           "title": "Preferred Editor",
           "description": "The preferred editor to open files in.",