fix: stop multi-critical P1 escalation from dragging up unrelated low issues

_determine_ticket_priority returned P1 for EVERY issue in a scan whenever the
report had >= PRIORITY_ESCALATION_THRESHOLD criticals, because the critical
count is global to the health report. A benign P4 "high storage usage" or
"CPU usage" alert on a node that also had 3+ critical drive failures was
created as P1, flooding P1s.

Split the severity cascade into _base_issue_priority() and only apply the
multi-critical "cluster risk" P1 bump to issues that are themselves
critical/high-severity (base P1/P2). Routine warnings (P3) and normal alerts
(P4/P5) keep their base priority. Critical issues still escalate to P1 under
multi-critical conditions as before.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hwmonDaemon.py

@@ -1782,16 +1782,30 @@ class SystemHealthMonitor:
         P5 = Informational/minimal impact
         """
         issue_lower = issue.lower()
+        base = self._base_issue_priority(issue_lower)
 
-        # Count total critical issues for escalation logic
+        # Multi-critical "cluster risk" escalation: when several critical failures
+        # are occurring at once, raise the SERIOUS issues to P1. This must only
+        # apply to issues that are themselves critical/high-severity (base P1/P2);
+        # it must NOT drag routine warnings (P3) or normal alerts (P4/P5) up to P1
+        # just because unrelated criticals exist elsewhere on the node.
         critical_count = self._count_critical_issues(health_report)
         escalation_threshold = self.CONFIG.get('PRIORITY_ESCALATION_THRESHOLD', 3)
-
-        # P1 - Multiple simultaneous critical failures (cluster risk)
-        if critical_count >= escalation_threshold:
-            logger.info(f"P1 escalation triggered: {critical_count} critical issues detected")
+        if (critical_count >= escalation_threshold
+                and base in (self.PRIORITIES['CRITICAL'], self.PRIORITIES['HIGH'])):
+            logger.info(
+                f"P1 escalation: {critical_count} simultaneous critical issues; "
+                f"raising P{base} issue to P1"
+            )
             return self.PRIORITIES['CRITICAL']  # P1
 
+        return base
+
+    def _base_issue_priority(self, issue_lower: str) -> str:
+        """
+        Severity-based priority for a single issue, with no cross-issue escalation.
+        _determine_ticket_priority layers the multi-critical P1 escalation on top.
+        """
         # P1 - Specific cluster-affecting scenarios
         if any(keyword in issue_lower for keyword in [
             'raid degraded', 'multiple drive',