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/V5Model.php

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