Add Northflank connection support

- Introduced Northflank as a new app connection option, including API token authentication.
- Implemented connection schemas, validation, and service functions for Northflank.
- Updated API documentation to include Northflank endpoints and integration instructions.
- Added frontend components for creating and managing Northflank connections.

docs/integrations/app-connections/northflank.mdx

@@ -0,0 +1,123 @@
+---
+title: "Northflank Connection"
+description: "Learn how to configure a Northflank Connection for Infisical."
+---
+
+Infisical supports the use of [API Tokens](https://northflank.com/docs/v1/api/use-the-api) to connect with Northflank.
+
+<Tip>
+  Infisical recommends creating a specific API role for the app connection and only giving access to projects that will use the integration.
+</Tip>
+
+## Create a Northflank API Token
+
+<Steps>
+  <Step title="Create an API Role">
+    Navigate to your team page and click **Create token**.
+
+    ![Create API Role](/images/app-connections/northflank/step-1.png)
+
+    Click in **Create API role**.
+
+    ![Create API Role](/images/app-connections/northflank/step-2.png)
+
+    Select all the projects you want this role to have access, or leave this unchecked if you want to give access to all project.
+
+    ![Create API Role](/images/app-connections/northflank/step-3.png)
+
+    Add the **Projects** -> **Manage** -> **Read** permission.
+
+    ![Create API Role](/images/app-connections/northflank/step-4.png)
+
+    Scroll to the bottom and save the API role.
+  </Step>
+  <Step title="Create an API Token">
+    Click on the **API** -> **Tokens** menu on the left and then in the **Create API token** button.
+
+    ![Create API Token](/images/app-connections/northflank/step-5.png)
+
+    Give a name to the API token and click the **Use role** button for the new API role you just created.
+
+    ![Create API Token](/images/app-connections/northflank/step-6.png)
+
+    Click the **View API token** icon to view and copy your token.
+
+    ![Create API Token](/images/app-connections/northflank/step-7.png)
+  </Step>
+</Steps>
+
+## Create a Northflank Connection in Infisical
+
+<Tabs>
+  <Tab title="Infisical UI">
+    <Steps>
+      <Step title="Navigate to App Connections">
+        In your Infisical dashboard, navigate to the **App Connections** page in the desired project.
+
+        ![App Connections Tab](/images/app-connections/general/add-connection.png)
+      </Step>
+      <Step title="Select Northflank Connection">
+        Click **+ Add Connection** and choose **Northflank Connection** from the list of integrations.
+
+        ![Select Northflank Connection](/images/app-connections/northflank/northflank-app-connection-option.png)
+      </Step>
+      <Step title="Fill out the Northflank Connection form">
+        Complete the form by providing:
+        - A descriptive name for the connection
+        - An optional description
+        - The API Token from the previous step
+
+        ![Northflank Connection Modal](/images/app-connections/northflank/northflank-app-connection-form.png)
+      </Step>
+      <Step title="Connection created">
+        After submitting the form, your **Northflank Connection** will be successfully created and ready to use with your Infisical project.
+
+        ![Northflank Connection Created](/images/app-connections/northflank/northflank-app-connection-generated.png)
+      </Step>
+    </Steps>
+  </Tab>
+
+  <Tab title="API">
+    To create a Northflank Connection via API, send a request to the [Create Northflank Connection](/api-reference/endpoints/app-connections/northflank/create) endpoint.
+
+    ### Sample request
+
+    ```bash Request
+    curl    --request POST \
+            --url http://localhost:8080/api/v1/app-connections/northflank \
+            --header 'Content-Type: application/json' \
+            --data '{
+                "name": "my-northflank-connection",
+                "method": "api-token",
+                "projectId": "abcdef12-3456-7890-abcd-ef1234567890",
+                "credentials": {
+                    "apiToken": "[API TOKEN]"
+                }
+            }'
+    ```
+
+    ### Sample response
+
+    ```bash Response
+    {
+      "appConnection": {
+          "id": "a1b2c3d4-5678-90ab-cdef-1234567890ab",
+          "name": "my-northflank-connection",
+          "description": null,
+          "projectId": "7ffbb072-2575-495a-b5b0-127f88caef78",
+          "version": 1,
+          "orgId": "abcdef12-3456-7890-abcd-ef1234567890",
+          "createdAt": "2025-01-23T10:15:00.000Z",
+          "updatedAt": "2025-01-23T10:15:00.000Z",
+          "isPlatformManagedCredentials": false,
+          "credentialsHash": "d41d8cd98f00b204e9800998ecf8427e",
+          "gatewayId":null,
+          "projectId":"abcdef12-3456-7890-abcd-ef1234567890"
+          "app": "northflank",
+          "method": "api-token",
+          "credentials": {}
+      }
+    }
+    ```
+  </Tab>
+</Tabs>