docs: add authentication page (#727)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

apps/docs/authentication.mdx

@@ -0,0 +1,101 @@
+---
+title: Authentication
+description: API keys, scoped keys, and connector branding.
+icon: "key"
+---
+
+## API Keys
+
+All API requests require authentication using a Bearer token. Get your API key from the [Developer Platform](https://console.supermemory.ai).
+
+<Snippet file="getting-api-key.mdx" />
+
+Include your key in all requests:
+
+<CodeGroup>
+
+```bash cURL
+curl https://api.supermemory.ai/v3/search \
+  --header 'Authorization: Bearer YOUR_API_KEY' \
+  --header 'Content-Type: application/json' \
+  -d '{"q": "hello"}'
+```
+
+```typescript TypeScript
+import Supermemory from "supermemory";
+
+const client = new Supermemory({ apiKey: "YOUR_API_KEY" });
+```
+
+```python Python
+from supermemory import Supermemory
+
+client = Supermemory(api_key="YOUR_API_KEY")
+```
+
+</CodeGroup>
+
+---
+
+## Connector Branding
+
+When users connect external services (Google Drive, Notion, OneDrive), they see a "Log in to **Supermemory**" prompt by default. You can replace this with your own app name by providing your own OAuth credentials via the settings endpoint.
+
+```typescript
+await client.settings.update({
+  googleDriveCustomKeyEnabled: true,
+  googleDriveClientId: "your-client-id.apps.googleusercontent.com",
+  googleDriveClientSecret: "your-client-secret"
+});
+```
+
+This works for Google Drive, Notion, and OneDrive. See the full setup in [Customization](/concepts/customization).
+
+---
+
+## Scoped API Keys
+
+<Accordion title="Container-scoped keys" icon="lock">
+  Scoped keys are restricted to a single `containerTag`. They can only access documents and search within that container — useful for giving limited access to specific projects, users, or tenants without exposing your full API key.
+
+  **Allowed endpoints:** `/v3/documents`, `/v3/memories`, `/v4/memories`, `/v3/search`, `/v4/search`, `/v4/profile`
+
+  ### Create a scoped key
+
+  ```bash
+  curl https://api.supermemory.ai/api/auth/scoped-key \
+    --request POST \
+    --header 'Content-Type: application/json' \
+    --header 'Authorization: Bearer YOUR_API_KEY' \
+    -d '{
+      "containerTag": "my-project",
+      "name": "my-key-name",
+      "expiresInDays": 30
+    }'
+  ```
+
+  ### Parameters
+
+  | Parameter | Required | Default | Description |
+  |-----------|----------|---------|-------------|
+  | `containerTag` | Yes | — | Alphanumeric, hyphens, underscores, colons, dots |
+  | `name` | No | `scoped_{containerTag}` | Display name for the key |
+  | `expiresInDays` | No | — | 1–365 days |
+  | `rateLimitMax` | No | `500` | Max requests per window (1–10,000) |
+  | `rateLimitTimeWindow` | No | `60000` | Window in milliseconds (1–3,600,000) |
+
+  ### Response
+
+  ```json
+  {
+    "key": "sm_orgId_...",
+    "id": "key-id",
+    "name": "scoped_my-project",
+    "containerTag": "my-project",
+    "expiresAt": "2026-03-08T00:00:00.000Z",
+    "allowedEndpoints": ["/v3/documents", "/v3/memories", "/v4/memories", "/v3/search", "/v4/search", "/v4/profile"]
+  }
+  ```
+
+  Use the returned key exactly like a normal API key — it just won't work outside its container scope.
+</Accordion>

apps/docs/docs.json

@@ -81,7 +81,8 @@
 									"concepts/memory-vs-rag",
 									"concepts/filtering",
 									"concepts/user-profiles",
-									"concepts/customization"
+									"concepts/customization",
+									"authentication"
 								]
 							},
 							{