feat(v5): add Inertia app shell with Flux health

Adds v5 routing, middleware, home page rendering, team context sharing,
project model/table support, and Flux health reporting. Installs Flux in
container builds with role-aware s6 services and documents runtime roles.

app/Models/V5/Project.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace App\Models\V5;
+
+use App\Models\Team;
+use App\Models\User;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Project extends V5Model
+{
+    protected $table = 'v5_projects';
+
+    protected $fillable = [
+        'team_id',
+        'created_by_user_id',
+        'name',
+        'description',
+    ];
+
+    public function team(): BelongsTo
+    {
+        return $this->belongsTo(Team::class);
+    }
+
+    public function creator(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'created_by_user_id');
+    }
+}

app/Models/V5/V5Model.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace App\Models\V5;
+
+use Illuminate\Database\Eloquent\Model;
+
+abstract class V5Model extends Model
+{
+    //
+}