restore: bring back f8a1310 (security review) state

Restores all files to the f8a1310 security-review snapshot as requested,
plus the 2 boot-critical fixes from a24c8a2 (config/session.php env()
instead of app()->environment(), and removal of the duplicate $activeTab
in ProjectMap.php) so the application actually boots.

Forward commit, no history rewrite. The 7d854ff state remains in history.

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

app/Livewire/ProjectCompanies.php

@@ -17,6 +17,10 @@ class ProjectCompanies extends Component
 
     public function mount(Project $project)
     {
+        $user = Auth::user();
+        if (!$user->hasRole('Admin') && !$project->users()->where('user_id', $user->id)->exists()) {
+            abort(403);
+        }
         $this->project = $project;
         $this->loadCompanies();
     }
@@ -65,6 +69,11 @@ class ProjectCompanies extends Component
 
     public function changeRole($companyId, $role)
     {
+        $user = Auth::user();
+        if (!$user->can('assign users') && !$user->hasRole('Admin')) {
+            session()->flash('error', 'Sin permisos.');
+            return;
+        }
         if (!in_array($role, ['owner', 'constructor', 'subcontractor', 'consultant', 'supplier', 'other'])) return;
 
         $this->project->companies()->updateExistingPivot($companyId, [