fix(telegram): back off on transient polling failures

Give getUpdates a wider HTTP timeout than the long-poll window, log transient SSL/network disconnects as warnings, apply exponential backoff with recovery logging, and only escalate to error after five consecutive failures.

reaction_board/services/telegram_poller.py

@@ -88,11 +88,41 @@ class TelegramPoller:
             self._log("warning", "telegram.answer_failed", error=str(exc))
             return False
 
-    def run_forever(self, stop_event=None) -> None:
+    def run_forever(
+        self,
+        stop_event=None,
+        *,
+        initial_delay: float = 3.0,
+        max_delay: float = 60.0,
+        max_iterations: int | None = None,
+    ) -> None:
         offset: int | None = None
+        failures = 0
+        delay = initial_delay
+        iterations = 0
         while stop_event is None or not stop_event.is_set():
             try:
                 offset = self.run_once(offset)
-            except Exception as exc:  # noqa: BLE001  长轮询失败后退避重试
-                self._log("error", "telegram.poll_failed", error=str(exc))
-                self._sleep(3)
+            except Exception as exc:  # noqa: BLE001  长轮询瞬时断连后退避重试
+                failures += 1
+                level = "error" if failures >= 5 else "warning"
+                self._log(
+                    level, "telegram.poll_failed",
+                    error=str(exc), failures=failures, retry_in=delay,
+                )
+                if stop_event is not None:
+                    if stop_event.wait(delay):
+                        break
+                else:
+                    self._sleep(delay)
+                delay = min(delay * 2, max_delay)
+            else:
+                if failures:
+                    self._log(
+                        "info", "telegram.poll_recovered", failures=failures
+                    )
+                failures = 0
+                delay = initial_delay
+            iterations += 1
+            if max_iterations is not None and iterations >= max_iterations:
+                break