feat(Linear Node): Add support for OAuth2 (#7201)

packages/nodes-base/credentials/LinearOAuth2Api.credentials.ts

@@ -0,0 +1,73 @@
+import type { ICredentialType, INodeProperties } from 'n8n-workflow';
+
+const scopes = ['read', 'write', 'issues:create', 'comments:create'];
+
+export class LinearOAuth2Api implements ICredentialType {
+	name = 'linearOAuth2Api';
+
+	extends = ['oAuth2Api'];
+
+	displayName = 'Linear OAuth2 API';
+
+	documentationUrl = 'linear';
+
+	properties: INodeProperties[] = [
+		{
+			displayName: 'Grant Type',
+			name: 'grantType',
+			type: 'hidden',
+			default: 'authorizationCode',
+		},
+		{
+			displayName: 'Authorization URL',
+			name: 'authUrl',
+			type: 'hidden',
+			default: 'https://linear.app/oauth/authorize',
+			required: true,
+		},
+		{
+			displayName: 'Access Token URL',
+			name: 'accessTokenUrl',
+			type: 'hidden',
+			default: 'https://api.linear.app/oauth/token',
+			required: true,
+		},
+		{
+			displayName: 'Actor',
+			name: 'actor',
+			type: 'options',
+			options: [
+				{
+					name: 'User',
+					value: 'user',
+					description: 'Resources are created as the user who authorized the application',
+				},
+				{
+					name: 'Application',
+					value: 'application',
+					description: 'Resources are created as the application',
+				},
+			],
+			default: 'user',
+		},
+		{
+			displayName: 'Scope',
+			name: 'scope',
+			type: 'hidden',
+			default: scopes.join(' '),
+			required: true,
+		},
+		{
+			displayName: 'Auth URI Query Parameters',
+			name: 'authQueryParameters',
+			type: 'hidden',
+			default: '={{"actor="+$self["actor"]}}',
+		},
+		{
+			displayName: 'Authentication',
+			name: 'authentication',
+			type: 'hidden',
+			default: 'body',
+		},
+	];
+}