docs: add Google OAuth, update login methods and token info

Add Google SSO section to Account Security page alongside GitHub.
Update login methods table with all four options. Update quickstart
to mention Google/GitHub sign-up and remove outdated admin token
one-time display note (tokens are now created from the console).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Ignacio Van Droogenbroeck

docs-arc-cloud/getting-started/quickstart.md

@@ -8,7 +8,7 @@ Get up and running with Arc Cloud in under a minute.
 
 ## 1. Sign Up
 
-Create a free account at [cloud.arc.basekick.net/signup](https://cloud.arc.basekick.net/signup). No credit card required.
+Create a free account at [cloud.arc.basekick.net/signup](https://cloud.arc.basekick.net/signup). No credit card required. You can sign up with email and password, or use **Google** or **GitHub** for one-click registration.
 
 ## 2. Create an Instance
 
@@ -23,11 +23,7 @@ Your instance will be ready in approximately 30 seconds. The status indicator wi
 Once provisioning completes, you will see:
 
 - **Endpoint URL**: `https://<instance-id>.arc.<region>.basekick.net`
-- **Admin Token**: A one-time token displayed on screen
-
-:::warning Save Your Admin Token
-The admin token is shown **only once** during provisioning. Copy it immediately and store it securely. If you lose it, you will need to restart the instance to generate a new one.
-:::
+To connect to your instance externally (curl, SDK, Telegraf), create an API token from the **Tokens** tab in the instance console.
 
 ## 5. Send Your First Query
 

docs-arc-cloud/security-team/security.md

@@ -53,10 +53,27 @@ On the login page, click **Sign in with passkey**. Your browser will prompt you
 
 View and delete registered passkeys from **Settings** > **Security**. Deleting a passkey removes it permanently — you will no longer be able to use that credential to sign in.
 
+## Single Sign-On (OAuth)
+
+Arc Cloud supports signing in with third-party identity providers so you can skip creating a separate password.
+
+### GitHub
+
+Click **Continue with GitHub** on the login or signup page. Arc Cloud requests read-only access to your GitHub profile and email. Your account is linked by your GitHub ID — if you already have an Arc Cloud account with the same email, you will be asked to sign in with your password first and then link GitHub from Settings.
+
+### Google
+
+Click **Continue with Google** on the login or signup page. Arc Cloud requests access to your basic profile information (name and email). As with GitHub, your account is linked by your Google ID. If an account with the same email already exists, you must sign in with your password first.
+
+:::info
+OAuth accounts are auto-verified — no email confirmation step is required. A default organization is created automatically on first sign-in.
+:::
+
 ## Login Methods
 
-| Method | MFA Required |
-|--------|-------------|
-| Email + password | Yes, if 2FA is enabled |
-| Passkey | No — inherently multi-factor |
-| GitHub OAuth | No — relies on GitHub's own 2FA |
+| Method | MFA Required | Notes |
+|--------|-------------|-------|
+| Email + password | Yes, if 2FA is enabled | Standard sign-in flow |
+| Passkey | No — inherently multi-factor | Touch ID, Face ID, or security key |
+| GitHub OAuth | No — relies on GitHub's own security | Links by GitHub ID |
+| Google OAuth | No — relies on Google's own security | Links by Google ID |