feat: multi-server switcher + fleet context

- WithFleetContext concern: resolves the active server (session, default first
  online) + the fleet.
- ServerSwitcher Livewire component in the persistent sidebar: dropdown of the
  fleet; selecting persists active_server_id in the session and re-navigates so
  panels reflect the choice.
- Dashboard reacts: resource rings + panel subtitles follow the active server.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/Livewire/Concerns/WithFleetContext.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace App\Livewire\Concerns;
+
+use App\Models\Server;
+use Illuminate\Support\Collection;
+
+/**
+ * Shared fleet context for pages: the active server (from session, default
+ * first) plus the whole fleet. Real metrics come from the SSH layer later.
+ */
+trait WithFleetContext
+{
+    public function fleet(): Collection
+    {
+        return Server::orderBy('name')->get();
+    }
+
+    public function activeServer(): ?Server
+    {
+        $fleet = $this->fleet();
+
+        return $fleet->firstWhere('id', session('active_server_id'))
+            ?? $fleet->firstWhere('status', 'online')
+            ?? $fleet->first();
+    }
+}

app/Livewire/Dashboard.php

@@ -2,6 +2,7 @@
 
 namespace App\Livewire;
 
+use App\Livewire\Concerns\WithFleetContext;
 use Livewire\Attributes\Layout;
 use Livewire\Attributes\Title;
 use Livewire\Component;
@@ -10,6 +11,8 @@ use Livewire\Component;
 #[Title('Clusev — Dashboard')]
 class Dashboard extends Component
 {
+    use WithFleetContext;
+
     /**
      * Mock fleet data. Replaced by the SSH layer (phpseclib) + Reverb later.
      * Shapes mirror what MetricsPoller/FleetService will return.
@@ -52,6 +55,6 @@ class Dashboard extends Component
 
     public function render()
     {
-        return view('livewire.dashboard');
+        return view('livewire.dashboard', ['active' => $this->activeServer()]);
     }
 }

app/Livewire/ServerSwitcher.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Livewire;
+
+use App\Models\Server;
+use Livewire\Component;
+
+/**
+ * Sidebar fleet switcher. Lives in the persistent layout, so it survives
+ * wire:navigate. Selecting a server stores it in the session and reloads the
+ * current page so every panel reflects the new active server.
+ */
+class ServerSwitcher extends Component
+{
+    public function select(string $uuid): void
+    {
+        $server = Server::where('uuid', $uuid)->firstOrFail();
+
+        session(['active_server_id' => $server->id]);
+
+        $this->redirect(request()->header('Referer') ?: route('dashboard'), navigate: true);
+    }
+
+    public function render()
+    {
+        $servers = Server::orderBy('name')->get();
+        $active = $servers->firstWhere('id', session('active_server_id'))
+            ?? $servers->firstWhere('status', 'online')
+            ?? $servers->first();
+
+        return view('livewire.server-switcher', [
+            'servers' => $servers,
+            'active' => $active,
+        ]);
+    }
+}

resources/views/components/sidebar.blade.php

@@ -16,17 +16,9 @@
         </button>
     </div>
 
-    {{-- Server switcher (mock) --}}
+    {{-- Server switcher --}}
     <div class="shrink-0 border-b border-line p-3">
-        <button type="button"
+        <livewire:server-switcher />
-                class="flex min-h-11 w-full items-center gap-2.5 rounded-md border border-line bg-inset px-3 py-2 text-left transition-colors hover:border-line-strong">
-            <x-status-dot status="online" :ping="true" />
-            <span class="min-w-0 flex-1">
-                <span class="block truncate text-sm text-ink">web-01</span>
-                <span class="block truncate font-mono text-[11px] text-ink-3">10.10.90.136</span>
-            </span>
-            <x-icon name="switcher" class="h-4 w-4 shrink-0 text-ink-3" />
-        </button>
     </div>
 
     {{-- Nav --}}

resources/views/livewire/dashboard.blade.php

@@ -31,7 +31,7 @@
 
     {{-- Live chart (2/3) + resource rings (1/3) --}}
     <div class="grid grid-cols-1 gap-3 lg:grid-cols-3">
-        <x-panel title="Live-Auslastung" subtitle="web-01 · CPU %" class="lg:col-span-2">
+        <x-panel title="Live-Auslastung" :subtitle="($active?->name ?? '—') . ' · CPU %'" class="lg:col-span-2">
             <x-slot:actions>
                 <x-badge tone="cyan">Reverb</x-badge>
             </x-slot:actions>
@@ -57,11 +57,11 @@
             </div>
         </x-panel>
 
-        <x-panel title="Ressourcen" subtitle="web-01">
+        <x-panel title="Ressourcen" :subtitle="$active?->name ?? '—'">
             <div class="grid grid-cols-3 gap-2">
-                <x-ring :value="$web['cpu']" label="CPU" :tone="$ringTone($web['cpu'])" />
+                <x-ring :value="$active?->cpu ?? 0" label="CPU" :tone="$ringTone($active?->cpu ?? 0)" />
-                <x-ring :value="$web['mem']" label="RAM" :tone="$ringTone($web['mem'])" />
+                <x-ring :value="$active?->mem ?? 0" label="RAM" :tone="$ringTone($active?->mem ?? 0)" />
-                <x-ring :value="$disk" label="Disk" :tone="$ringTone($disk)" />
+                <x-ring :value="$active?->disk ?? 0" label="Disk" :tone="$ringTone($active?->disk ?? 0)" />
             </div>
         </x-panel>
     </div>
@@ -82,7 +82,7 @@
             </div>
         </x-panel>
 
-        <x-panel title="systemd-Dienste" subtitle="web-01" :padded="false">
+        <x-panel title="systemd-Dienste" :subtitle="$active?->name" :padded="false">
             <div class="divide-y divide-line">
                 @foreach ($services as $svc)
                     <div class="flex items-center gap-3 px-4 py-2.5 sm:px-5">

resources/views/livewire/server-switcher.blade.php

@@ -0,0 +1,40 @@
+<div x-data="{ open: false }" @click.outside="open = false" @keydown.escape="open = false" class="relative">
+    <button type="button" @click="open = ! open"
+            class="flex min-h-11 w-full items-center gap-2.5 rounded-md border border-line bg-inset px-3 py-2 text-left transition-colors hover:border-line-strong"
+            :aria-expanded="open" aria-haspopup="listbox">
+        @if ($active)
+            <x-status-dot :status="$active->status" :ping="$active->status === 'online'" />
+            <span class="min-w-0 flex-1">
+                <span class="block truncate font-mono text-sm text-ink">{{ $active->name }}</span>
+                <span class="block truncate font-mono text-[11px] text-ink-3">{{ $active->ip }}</span>
+            </span>
+        @else
+            <span class="min-w-0 flex-1 text-sm text-ink-3">Kein Server</span>
+        @endif
+        <x-icon name="switcher" class="h-4 w-4 shrink-0 text-ink-3" />
+    </button>
+
+    <div x-show="open" x-cloak x-transition.origin.top
+         class="absolute inset-x-0 top-full z-50 mt-1 overflow-hidden rounded-md border border-line bg-raised shadow-pop"
+         role="listbox">
+        <div class="max-h-72 overflow-y-auto p-1">
+            @foreach ($servers as $server)
+                <button type="button" wire:click="select('{{ $server->uuid }}')" @click="open = false"
+                        @class([
+                            'flex min-h-11 w-full items-center gap-2.5 rounded-sm px-2.5 py-1.5 text-left transition-colors hover:bg-surface',
+                            'bg-accent/10' => $active && $server->id === $active->id,
+                        ])
+                        role="option" :aria-selected="{{ $active && $server->id === $active->id ? 'true' : 'false' }}">
+                    <x-status-dot :status="$server->status" :ping="$server->status === 'online'" />
+                    <span class="min-w-0 flex-1">
+                        <span class="block truncate font-mono text-sm text-ink">{{ $server->name }}</span>
+                        <span class="block truncate font-mono text-[11px] text-ink-3">{{ $server->ip }} · {{ $server->os }}</span>
+                    </span>
+                    @if ($active && $server->id === $active->id)
+                        <x-icon name="activity" class="h-3.5 w-3.5 shrink-0 text-accent" />
+                    @endif
+                </button>
+            @endforeach
+        </div>
+    </div>
+</div>