[#121] added error handler and snackbar

src/components/Error/EventErrorHandler.ts

@@ -0,0 +1,25 @@
+export class EventErrorHandler {
+  private errors = new Map<string, string>();
+  private onErrorCallback?: (messages: string[]) => void;
+
+  setErrorCallback(callback: (messages: string[]) => void) {
+    this.onErrorCallback = callback;
+  }
+
+  reportError(eventId: string, message: string) {
+    if (!this.errors.has(eventId)) {
+      this.errors.set(eventId, message);
+      console.warn(`[EventErrorHandler] ${eventId}: ${message}`);
+      this.emit();
+    }
+  }
+
+  clearAll() {
+    this.errors.clear();
+    this.emit();
+  }
+
+  private emit() {
+    this.onErrorCallback?.(Array.from(this.errors.values()));
+  }
+}