feat(oauth): add OAuth token support

ts/bunq.classes.account.ts

@@ -9,6 +9,7 @@ export interface IBunqConstructorOptions {
   apiKey: string;
   environment: 'SANDBOX' | 'PRODUCTION';
   permittedIps?: string[];
+  isOAuthToken?: boolean; // Set to true when using OAuth access token instead of API key
 }
 
 /**
@@ -35,7 +36,8 @@ export class BunqAccount {
       apiKey: this.options.apiKey,
       environment: this.options.environment,
       deviceDescription: this.options.deviceName,
-      permittedIps: this.options.permittedIps
+      permittedIps: this.options.permittedIps,
+      isOAuthToken: this.options.isOAuthToken
     });
 
     // Initialize API context (handles installation, device registration, session)

ts/bunq.classes.apicontext.ts

@@ -9,6 +9,7 @@ export interface IBunqApiContextOptions {
   environment: 'SANDBOX' | 'PRODUCTION';
   deviceDescription: string;
   permittedIps?: string[];
+  isOAuthToken?: boolean;
 }
 
 export class BunqApiContext {
@@ -43,6 +44,15 @@ export class BunqApiContext {
    * Initialize the API context (installation, device, session)
    */
   public async init(): Promise<void> {
+    // If using OAuth token, skip session creation
+    if (this.options.isOAuthToken) {
+      // OAuth tokens already have an associated session
+      this.context.sessionToken = this.options.apiKey;
+      this.session = new BunqSession(this.crypto, this.context);
+      this.session.setOAuthMode(true);
+      return;
+    }
+    
     // Try to load existing context
     const existingContext = await this.loadContext();
     
@@ -125,6 +135,11 @@ export class BunqApiContext {
    * Refresh session if needed
    */
   public async ensureValidSession(): Promise<void> {
+    // OAuth tokens don't need session refresh
+    if (this.options.isOAuthToken) {
+      return;
+    }
+    
     await this.session.refreshSession();
     await this.saveContext();
   }

ts/bunq.classes.session.ts

@@ -13,6 +13,7 @@ export class BunqSession {
   private crypto: BunqCrypto;
   private context: IBunqApiContext;
   private sessionExpiryTime: plugins.smarttime.TimeStamp;
+  private isOAuthMode: boolean = false;
 
   constructor(crypto: BunqCrypto, context: IBunqApiContext) {
     this.crypto = crypto;
@@ -139,10 +140,27 @@ export class BunqSession {
     this.sessionExpiryTime = plugins.smarttime.TimeStamp.fromMilliSeconds(Date.now() + 600000);
   }
 
+  /**
+   * Set OAuth mode
+   */
+  public setOAuthMode(isOAuth: boolean): void {
+    this.isOAuthMode = isOAuth;
+    if (isOAuth) {
+      // OAuth tokens don't expire in the same way as regular sessions
+      // Set a far future expiry time
+      this.sessionExpiryTime = plugins.smarttime.TimeStamp.fromMilliSeconds(Date.now() + 365 * 24 * 60 * 60 * 1000);
+    }
+  }
+
   /**
    * Check if session is still valid
    */
   public isSessionValid(): boolean {
+    // OAuth tokens are always considered valid (they have their own expiry mechanism)
+    if (this.isOAuthMode) {
+      return true;
+    }
+    
     if (!this.sessionExpiryTime) {
       return false;
     }
@@ -155,6 +173,11 @@ export class BunqSession {
    * Refresh the session if needed
    */
   public async refreshSession(): Promise<void> {
+    // OAuth tokens don't need session refresh
+    if (this.isOAuthMode) {
+      return;
+    }
+    
     if (!this.isSessionValid()) {
       await this.createSession();
     }