refactor(platform): replace platform checks with capability-based system

- Add PlatformCapabilities interface to define available features
- Remove isWeb(), isCapacitor(), isElectron(), isPyWebView() methods
- Update platform services to implement getCapabilities()
- Refactor DataExportSection to use capability checks instead of platform checks
- Improve platform abstraction and separation of concerns
- Make platform-specific logic more maintainable and extensible

This change decouples components from specific platform implementations,
making the codebase more maintainable and easier to extend with new platforms.

src/services/platforms/WebPlatformService.ts

@@ -1,4 +1,4 @@
-import { ImageResult, PlatformService } from "../PlatformService";
+import { ImageResult, PlatformService, PlatformCapabilities } from "../PlatformService";
 import { logger } from "../../utils/logger";
 
 /**
@@ -15,6 +15,21 @@ import { logger } from "../../utils/logger";
  * due to browser security restrictions. These methods throw appropriate errors.
  */
 export class WebPlatformService implements PlatformService {
+  /**
+   * Gets the capabilities of the web platform
+   * @returns Platform capabilities object
+   */
+  getCapabilities(): PlatformCapabilities {
+    return {
+      hasFileSystem: false,
+      hasCamera: true, // Through file input with capture
+      isMobile: /iPhone|iPad|iPod|Android/i.test(navigator.userAgent),
+      isIOS: /iPad|iPhone|iPod/.test(navigator.userAgent),
+      hasFileDownload: true,
+      needsFileHandlingInstructions: false
+    };
+  }
+
   /**
    * Not supported in web platform.
    * @param _path - Unused path parameter