fix(docker): honest "not installed" state instead of a raw shell error

When a fleet host has no container runtime at all (e.g. a native
postfix/dovecot mail server), `docker ps` returns "sh: docker: not
found". The page surfaced that raw shell text inside a red error box,
which reads as a broken feature — the user reasonably expected the tab
to show containers.

Probe `available()` first: if the docker binary is genuinely absent,
render a clean, neutral "Docker nicht installiert — es gibt keine
Container zum Anzeigen" panel (box icon, no alarm styling) rather than
the shell error. A real fault (daemon down / permission) still shows
the actual error as before. Verified end-to-end against a real SSH host
with no runtime (the honest state) and against a real docker host (full
container list + Logs/Restart/Stop actions render).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/Livewire/Docker/Index.php

@@ -29,6 +29,9 @@ class Index extends Component
 
     public bool $ready = false;
 
+    /** Docker binary absent on the host (e.g. a native mail server) — an honest state, not an error. */
+    public bool $notInstalled = false;
+
     /** The docker error (daemon down / permission / rootless), surfaced so "empty" isn't misleading. */
     public ?string $error = null;
 
@@ -41,13 +44,20 @@ class Index extends Component
     {
         $this->containers = [];
         $this->connected = false;
+        $this->notInstalled = false;
         $this->error = null;
 
         $active = $this->activeServer();
         if ($active && $active->credential_exists) {
             try {
+                // Probe first: a host with no docker binary (native mail/web server) gets a clean
+                // "not installed" panel instead of the raw "sh: docker: not found" shell error.
+                if (! $docker->available($active)) {
+                    $this->notInstalled = true;
+                } else {
                     $this->containers = $docker->containers($active);
                     $this->connected = true;
+                }
             } catch (Throwable $e) {
                 $this->connected = false;
                 $this->error = mb_scrub(mb_strcut($e->getMessage(), 0, 300), 'UTF-8');

lang/de/docker.php

@@ -8,7 +8,9 @@ return [
     'disconnected' => 'Getrennt',
 
     'unavailable_title' => 'Docker nicht verfügbar',
-    'unavailable_hint' => 'Kein Docker auf diesem Server, Daemon aus, oder keine Berechtigung.',
+    'unavailable_hint' => 'Daemon aus oder keine Berechtigung.',
+    'not_installed_title' => 'Docker nicht installiert',
+    'not_installed_hint' => 'Auf diesem Server ist kein Docker installiert – es gibt keine Container zum Anzeigen.',
     'empty_title' => 'Keine Container',
     'empty_hint' => 'Auf diesem Server laufen keine Container.',
 

lang/en/docker.php

@@ -8,7 +8,9 @@ return [
     'disconnected' => 'Disconnected',
 
     'unavailable_title' => 'Docker unavailable',
-    'unavailable_hint' => 'No Docker on this server, the daemon is down, or no permission.',
+    'unavailable_hint' => 'The daemon is down, or no permission.',
+    'not_installed_title' => 'Docker not installed',
+    'not_installed_hint' => 'This server has no Docker installed – there are no containers to show.',
     'empty_title' => 'No containers',
     'empty_hint' => 'No containers are running on this server.',
 

resources/views/livewire/docker/index.blade.php

@@ -26,6 +26,15 @@
                     <div class="h-12 animate-pulse rounded-md bg-raised/50"></div>
                 @endfor
             </div>
+        @elseif ($notInstalled)
+            {{-- Honest, neutral state: the host simply has no docker (not a fault). --}}
+            <div class="px-4 py-10 text-center sm:px-5">
+                <div class="mx-auto flex h-10 w-10 items-center justify-center rounded-full bg-raised text-ink-3">
+                    <x-icon name="box" class="h-5 w-5" />
+                </div>
+                <p class="mt-3 text-sm text-ink-2">{{ __('docker.not_installed_title') }}</p>
+                <p class="mx-auto mt-1 max-w-md font-mono text-[11px] text-ink-4">{{ __('docker.not_installed_hint') }}</p>
+            </div>
         @elseif (! $connected)
             <div class="px-4 py-10 text-center sm:px-5">
                 <p class="text-sm text-ink-2">{{ __('docker.unavailable_title') }}</p>

tests/Feature/DockerComponentTest.php

@@ -49,6 +49,7 @@ class DockerComponentTest extends TestCase
     private function stubDocker(array $containers = []): DockerService
     {
         $docker = Mockery::mock(DockerService::class);
+        $docker->shouldReceive('available')->andReturn(true);
         $docker->shouldReceive('containers')->andReturn($containers);
         app()->instance(DockerService::class, $docker);
 
@@ -68,6 +69,28 @@ class DockerComponentTest extends TestCase
             ->assertSee('web');
     }
 
+    public function test_shows_a_clean_not_installed_state_when_docker_is_absent(): void
+    {
+        // A host without a container runtime (e.g. a native postfix/dovecot mail server) must NOT
+        // render the raw "sh: 1: docker: not found" shell error — that reads as a broken feature.
+        // available() is probed first; false => a clean, honest "not installed" panel.
+        $this->actingAs($this->viewer());
+        $this->activeServer();
+        $docker = Mockery::mock(DockerService::class);
+        $docker->shouldReceive('available')->once()->andReturn(false);
+        $docker->shouldReceive('containers')->never(); // never even attempt ps when docker is absent
+        app()->instance(DockerService::class, $docker);
+
+        Livewire::test(Index::class)
+            ->call('load')
+            ->assertOk()
+            ->assertSet('connected', false)
+            ->assertSet('notInstalled', true)
+            ->assertSet('error', null)
+            ->assertSee(__('docker.not_installed_title'))
+            ->assertDontSee('not found');
+    }
+
     public function test_viewer_cannot_run_a_container_action(): void
     {
         $this->actingAs($this->viewer());