feat: Phase 6.1 - Split ProjectMap into traits (part 1)

- Create MapLayers trait (layer/phase visibility, filters)
- Create MapInspections trait (inspection CRUD, viewer, editor)
- Create MapIssues trait (issue count listeners)
- Create MapFeatures trait (feature selection, progress, images)

Tests: 101 passing (319 assertions)

app/Livewire/Projects/Traits/MapIssues.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace App\Livewire\Projects\Traits;
+
+use App\Models\Feature;
+use App\Models\Issue;
+use Livewire\Attributes\On;
+
+trait MapIssues
+{
+    public $openIssuesCount = 0;
+
+    #[On('issue-created')]
+    public function handleIssueCreated()
+    {
+        $this->openIssuesCount = Issue::where('project_id', $this->project->id)
+            ->where('status', 'open')
+            ->count();
+    }
+
+    #[On('issue-updated')]
+    public function handleIssueUpdated()
+    {
+        $this->openIssuesCount = Issue::where('project_id', $this->project->id)
+            ->where('status', 'open')
+            ->count();
+    }
+
+    #[On('issue-deleted')]
+    public function handleIssueDeleted()
+    {
+        $this->openIssuesCount = Issue::where('project_id', $this->project->id)
+            ->where('status', 'open')
+            ->count();
+    }
+}