feat: Implement OAuth2 authentication with Microsoft, Google, and PocketId

- Added JWT configuration to appsettings.json for secure token handling.
- Updated config.json to include OAuth provider details for Microsoft, Google, and PocketId.
- Added Microsoft icon SVG for UI representation.
- Refactored app.config.ts to use a custom AuthInterceptor for managing access tokens.
- Enhanced auth route guard to handle asynchronous authentication checks.
- Created new auth models for structured request and response handling.
- Developed a callback component to manage user login states and transitions.
- Updated side-login component to support multiple OAuth providers with loading states.
- Implemented authentication service methods for handling OAuth login flows and token management.
- Added error handling and user feedback for authentication processes.

Web/src/app/services/auth.interceptor.ts

@@ -0,0 +1,29 @@
+import { Injectable } from '@angular/core';
+import { HttpEvent, HttpHandler, HttpInterceptor, HttpRequest } from '@angular/common/http';
+import { Observable } from 'rxjs';
+import { AuthenticationService } from './authentication.service';
+
+@Injectable()
+export class AuthInterceptor implements HttpInterceptor {
+    constructor(private authService: AuthenticationService) { }
+
+    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+        // Skip adding auth header for authentication endpoints
+        if (req.url.includes('/api/auth/authenticate') || req.url.includes('/assets/')) {
+            return next.handle(req);
+        }
+
+        // Get custom access token
+        const token = this.authService.getCustomAccessToken();
+        
+        if (token) {
+            // Clone request and add Authorization header
+            const authReq = req.clone({
+                headers: req.headers.set('Authorization', `Bearer ${token}`)
+            });
+            return next.handle(authReq);
+        }
+
+        return next.handle(req);
+    }
+}