fix: preserve unknown health status in Sentinel updates (PushServerUpdateJob)

## Problem
Services with "running (unknown)" status were periodically changing
to "running (healthy)" every ~30 seconds when Sentinel pushed updates.
This was confusing for users and inconsistent with SSH-based status checks.

## Root Cause
`PushServerUpdateJob::aggregateMultiContainerStatuses()` was missing
logic to track "unknown" health state. It only tracked "unhealthy" and
defaulted everything else to "healthy".

When Sentinel pushed updates with "running (unknown)" containers:
- The job saw `hasRunning = true` and `hasUnhealthy = false`
- It incorrectly returned "running (healthy)" instead of "running (unknown)"

## Solution
Updated `PushServerUpdateJob` to match the logic in `GetContainersStatus`:

1. Added `$hasUnknown` tracking variable
2. Check for "unknown" in status strings (alongside "unhealthy")
3. Implement 3-way priority: unhealthy > unknown > healthy

This ensures consistency between:
- SSH-based updates (`GetContainersStatus`)
- Sentinel-based updates (`PushServerUpdateJob`)
- UI display logic

## Changes
- **app/Jobs/PushServerUpdateJob.php**: Added unknown status tracking
- **tests/Unit/PushServerUpdateJobStatusAggregationTest.php**: New comprehensive tests
- **tests/Unit/ExcludeFromHealthCheckTest.php**: Updated to match current implementation

## Testing
All 31 status-related unit tests passing:
- 18 tests in ContainerHealthStatusTest
- 8 tests in ExcludeFromHealthCheckTest (updated)
- 6 tests in PushServerUpdateJobStatusAggregationTest (new)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/Jobs/PushServerUpdateJob.php

@@ -269,6 +269,7 @@ class PushServerUpdateJob implements ShouldBeEncrypted, ShouldQueue, Silenced
             // Aggregate status: if any container is running, app is running
             $hasRunning = false;
             $hasUnhealthy = false;
+            $hasUnknown = false;
 
             foreach ($relevantStatuses as $status) {
                 if (str($status)->contains('running')) {
@@ -276,12 +277,21 @@ class PushServerUpdateJob implements ShouldBeEncrypted, ShouldQueue, Silenced
                     if (str($status)->contains('unhealthy')) {
                         $hasUnhealthy = true;
                     }
+                    if (str($status)->contains('unknown')) {
+                        $hasUnknown = true;
+                    }
                 }
             }
 
             $aggregatedStatus = null;
             if ($hasRunning) {
-                $aggregatedStatus = $hasUnhealthy ? 'running (unhealthy)' : 'running (healthy)';
+                if ($hasUnhealthy) {
+                    $aggregatedStatus = 'running (unhealthy)';
+                } elseif ($hasUnknown) {
+                    $aggregatedStatus = 'running (unknown)';
+                } else {
+                    $aggregatedStatus = 'running (healthy)';
+                }
             } else {
                 // All containers are exited
                 $aggregatedStatus = 'exited (unhealthy)';