Stage 07.4.3.2 — price polling, event bus and UI throttling

app/src/core/event_bus.py

@@ -0,0 +1,28 @@
+# app/src/core/event_bus.py
+
+from __future__ import annotations
+
+from typing import Any
+
+
+class EventBus:
+    _version: int = 0
+    _last_event_type: str | None = None
+    _last_payload: dict[str, Any] = {}
+
+    # зафиксировать важное событие системы
+    @classmethod
+    def emit(cls, event_type: str, payload: dict[str, Any] | None = None) -> None:
+        cls._version += 1
+        cls._last_event_type = event_type
+        cls._last_payload = payload or {}
+
+    # текущая версия событий
+    @classmethod
+    def version(cls) -> int:
+        return cls._version
+
+    # последнее событие
+    @classmethod
+    def last_event(cls) -> tuple[str | None, dict[str, Any]]:
+        return cls._last_event_type, dict(cls._last_payload)