fix(notifications): localize sensor alerts and preserve email context

AppImage/scripts/health_monitor.py

@@ -1586,6 +1586,9 @@ class HealthMonitor:
                             'temperature': max_temp, 'duration': actual_duration,
                             'dismissable': True, 'value': max_temp, 'threshold': 80,
                             'details': f'High samples span {duration_str}.',
+                            # Explicit provenance for render-time localization;
+                            # older/manual detail strings remain verbatim.
+                            'temperature_detail_kind': 'high_samples_span',
                         }
                     )
                 elif len(recovery_samples) >= 3:

AppImage/scripts/notification_channels.py

@@ -1049,6 +1049,13 @@ class EmailChannel(NotificationChannel):
         # ── Build structured detail rows from known data fields ──
         detail_rows = self._build_detail_rows(data, event_type, group, html_mod)
 
+        # The temperature renderer has already validated whether both
+        # measurements exist and localized its sampled-span detail. Its body
+        # is authoritative: raw fields can otherwise print a misleading °C
+        # value for an incomplete manual/persisted payload and hide the body.
+        if event_type == 'temp_high':
+            detail_rows = []
+
         # Vzdump bodies are authoritative multi-item inventories. Keep their
         # lines exactly once, but retain the localized structured status row;
         # the remaining structured backup metadata only duplicates the report.
@@ -1093,7 +1100,7 @@ class EmailChannel(NotificationChannel):
         # ── Reason / details block (long text, displayed separately) ──
         reason = data.get('reason', '')
         reason_html = ''
-        if reason and len(reason) > 80:
+        if reason and len(reason) > 80 and not (event_type == 'temp_high' and reason in body):
             reason_html = f'''
 <div style="margin:16px 0 0;padding:12px 16px;border:1px solid #d1d5db;border-radius:6px;">
   <p style="margin:0 0 4px;font-size:11px;font-weight:600;color:#374151;text-transform:uppercase;letter-spacing:0.05em;">{_runtime_text('email.details', data)}</p>

AppImage/scripts/notification_templates.py

@@ -1899,13 +1899,25 @@ def render_template(event_type: str, data: Dict[str, Any],
             except (OverflowError, ValueError, TypeError):
                 return False
 
+        # Only the known sampler-generated detail is eligible: duration alone
+        # cannot establish provenance and manual/legacy text is not rewritten.
+        seconds = data.get('duration')
+        if (data.get('temperature_detail_kind') == 'high_samples_span'
+                and type(seconds) is int and 0 <= seconds <= 240):
+            span = (f'{seconds // 60}m {seconds % 60}s'
+                    if seconds >= 60 else f'{seconds}s')
+            if data.get('details') == f'High samples span {span}.':
+                variables['details'] = runtime_message(
+                    'temperature.sampleSpan', language, duration=span)
+
         if not all(finite_measurement(key) for key in ('value', 'threshold')):
-            template['title'] = runtime_message(
+            variables['_temperature_fallback_title'] = runtime_message(
                 'fallback.temperatureAlertTitle', language, hostname=variables['hostname'],
             )
+            template['title'] = '{_temperature_fallback_title}'
             lines = [runtime_message('fallback.temperatureAlertBody', language)]
             reason = data.get('reason')
-            details = data.get('details')
+            details = variables.get('details')
             reason = reason.strip() if isinstance(reason, str) else ''
             details = details.strip() if isinstance(details, str) else ''
             if reason:

AppImage/scripts/tests/test_notification_runtime_i18n.py

@@ -110,7 +110,12 @@ class RuntimeCatalogTests(unittest.TestCase):
         values.update({"hostname": "HOST-ŽILINA", "severity": "WARNING"})
         with mock.patch.object(notification_templates, "_get_hostname", return_value="HOST-ŽILINA"):
             for event_type in notification_templates.TEMPLATES:
-                rendered = notification_templates.render_template(event_type, values, language="sk")
+                event_values = dict(values)
+                if event_type == "temp_high":
+                    # Temperature is a measured numeric contract; arbitrary
+                    # DYNAMIC_VALUE is correctly rejected by its fallback.
+                    event_values.update(value="89", threshold="80")
+                rendered = notification_templates.render_template(event_type, event_values, language="sk")
                 combined = rendered["title"] + "\n" + rendered["body"]
                 if notification_templates.TEMPLATES[event_type].get("formatter"):
                     continue
@@ -119,7 +124,7 @@ class RuntimeCatalogTests(unittest.TestCase):
                     + notification_templates.TEMPLATES[event_type]["body"]
                 ):
                     if name not in {"entity_suffix", "title_or_default"}:
-                        self.assertIn(str(values[name]), combined, f"{event_type}:{name}")
+                        self.assertIn(str(event_values[name]), combined, f"{event_type}:{name}")
 
     def test_lxc_update_result_and_details_render_in_slovak(self):
         data = {