fix(eps): cap alarm texts per event to stop eps_alarm_history.json growing unbounded

A long-running/flapping EPS alarm appended every slightly-different
AlarmList_EPS text to the open event's texts list with no limit,
eventually growing eps_alarm_history.json past the upload server's
size limit (HTTP 413), which then retried and re-failed indefinitely.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XdHenMmwbrCz1juWMi1yZc

csaxs_bec/bec_ipython_client/plugins/OMNY_shared/eps/eps_status_generator.py

@@ -92,6 +92,9 @@ _HISTORY_MAX = 50             # events persisted per stream
 _HISTORY_SHOW = 5             # events surfaced to the page per stream
 _TRACE_MAX = 288              # ring-current samples (24 h at 5 min)
 _FLAP_COALESCE_S = 60         # re-alarm within this window extends the event
+_ALARM_TEXTS_MAX = 100        # distinct alarm texts kept on a single open eps_event;
+                               # only one event is ever open at a time, so this bounds
+                               # total history growth during a long-running flapping alarm
 
 _SEVERITY_NAMES = {0: "NO_ALARM", 1: "MINOR", 2: "MAJOR", 3: "INVALID"}
 
@@ -235,7 +238,9 @@ class HistoryTracker:
                 if open_ev is not None:
                     open_ev["count"] = max(open_ev.get("count", 0), count)
                     if text and text not in open_ev.get("texts", []):
-                        open_ev.setdefault("texts", []).append(text)
+                        texts = open_ev.setdefault("texts", [])
+                        texts.append(text)
+                        del texts[:-_ALARM_TEXTS_MAX]
                     return
                 # coalesce a rapid re-alarm with identical text
                 if self.eps_events: