fix: refresh reboot evidence after external host updates

AppImage/scripts/flask_health_routes.py

@@ -243,10 +243,14 @@ def get_full_health():
     security before returning, so an event that just changed underlying state
     (Update Now finished, dismiss action) sees the new value immediately
     instead of waiting for the next polling tick.
+    ?cached=1 is a strictly read-only poll: no full checks or cache clearing,
+    even with refresh=1. Unavailable/stale snapshots return 503. Every valid
+    response refreshes reboot evidence, while keeping the full audit's date.
     """
     import time as _time
     try:
-        if request.args.get('refresh') == '1':
+        cached_only = request.args.get('cached') == '1'
+        if not cached_only and request.args.get('refresh') == '1':
             for ck in ('updates_check', 'pve_services', 'security_check',
                        '_bg_detailed', '_bg_overall', 'overall_health'):
                 health_monitor.last_check_times.pop(ck, None)
@@ -255,14 +259,24 @@ def get_full_health():
         # Try to use the background-cached detailed result for instant response
         bg_key = '_bg_detailed'
         bg_last = health_monitor.last_check_times.get(bg_key, 0)
-        bg_age = _time.time() - bg_last
+        bg_age = _time.time() - bg_last if type(bg_last) in (int, float) else float('inf')
 
-        if bg_age < 360 and bg_key in health_monitor.cached_results:
+        if 0 <= bg_age < 360 and bg_key in health_monitor.cached_results:
             # Use cached result (at most ~5 min old)
             details = health_monitor.cached_results[bg_key]
+        elif cached_only:
+            # Automatic polling must never start APT or a full audit, even
+            # during startup, collector failure, expiry or a conflicting flag.
+            return jsonify({'error': 'Health snapshot is not available yet'}), 503
         else:
             # No fresh cache, run live (first load or cache expired)
             details = health_monitor.get_detailed_status()
+
+        # Installed/running kernel state changes outside Monitor jobs too.
+        # Overlay fresh read-only evidence without refreshing other checks or
+        # rewriting the background collector's snapshot/timestamp.
+        from kernel_reboot import refresh_health_reboot
+        details = refresh_health_reboot(details)
         
         active_errors = health_persistence.get_active_errors()
         dismissed = health_persistence.get_dismissed_errors()

AppImage/scripts/kernel_reboot.py

@@ -1,5 +1,6 @@
 """Read-only reboot evidence, independent of APT pending-update caches."""
 import os
+import copy
 from pathlib import Path
 import re
 import subprocess
@@ -63,6 +64,13 @@ def with_reboot_status(updates, reboot):
         return updates
     result = dict(updates or dict(status='UNKNOWN', count=None, checks={}))
     result['checks'] = dict(result.get('checks') or {})
+    # Keep the package result separate so a later reboot-only overlay can
+    # clear its own INFO/UNKNOWN without hiding a package-check failure.
+    base_status = result.get('package_status', result.get('status', 'UNKNOWN'))
+    if result.get('all_dismissed'):
+        base_status = 'OK'
+    result['package_status'] = base_status
+    result['status'] = base_status
     required = reboot['state'] == 'required'
     unknown = reboot['state'] == 'unknown'
     result['reboot_required'] = True if required else None if unknown else False
@@ -77,3 +85,32 @@ def with_reboot_status(updates, reboot):
     if result.get('status') == 'OK' and (required or unknown):
         result['status'] = 'INFO' if required else 'UNKNOWN'
     return result
+
+
+def refresh_health_reboot(snapshot):
+    """Refresh only reboot evidence on an immutable, dated health snapshot.
+
+    Never runs the full health check, APT, persistence writes or lifecycle
+    commands. Other categories and the audit timestamp retain their age.
+    """
+    result = copy.deepcopy(snapshot)
+    details = result.get('details')
+    if not isinstance(details, dict) or not isinstance(details.get('updates'), dict):
+        raise ValueError('Health snapshot has no updates result')
+    details['updates'] = with_reboot_status(details['updates'], reboot_status())
+    if details['updates']['status'] == snapshot['details']['updates']['status']:
+        return result
+    issues = {status: [] for status in ('CRITICAL', 'WARNING', 'UNKNOWN', 'INFO')}
+    for key, block in details.items():
+        if not isinstance(block, dict):
+            continue
+        status = block.get('status', 'UNKNOWN')
+        if status in issues:
+            label = key.replace('_', ' ').capitalize()
+            reason = block.get('reason')
+            issues[status].append(f'{label}: {reason}' if reason else label)
+    result['overall'] = ('CRITICAL' if issues['CRITICAL'] else 'WARNING'
+                         if issues['WARNING'] or issues['UNKNOWN'] else 'OK')
+    primary = next((values for values in issues.values() if values), [])
+    result['summary'] = '; '.join(primary) if primary else 'All systems operational'
+    return result