feat: add Projects settings with sub-locations and cascading dropdowns in purchase request modal

- Migration: add project_id FK to settings_locations
- Models: ProjectSetting hasMany Location, Location belongsTo ProjectSetting
- Settings: /settings/projects page — manage projects and their sub-locations (two-panel UI)
- Sidebar: Projects nav item under Settings group
- Routes: 7 new settings/projects routes (Admin only)
- Modal: project_name and location fields now cascading dropdowns populated from settings_projects/settings_locations

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

app/Http/Controllers/Settings/ProjectSettingController.php

@@ -3,6 +3,7 @@
 namespace App\Http\Controllers\Settings;
 
 use App\Http\Controllers\Controller;
+use App\Models\Settings\Location;
 use App\Models\Settings\ProjectSetting;
 use Illuminate\Http\Request;
 
@@ -10,7 +11,7 @@ class ProjectSettingController extends Controller
 {
     public function index()
     {
-        $projects = ProjectSetting::orderBy('name')->get();
+        $projects = ProjectSetting::with('locations')->orderBy('name')->get();
         return view('settings.projects.index', compact('projects'));
     }
 
@@ -36,4 +37,27 @@ class ProjectSettingController extends Controller
         $project->delete();
         return redirect()->route('settings.projects.index')->with('success', 'Project deleted.');
     }
+
+    public function storeLocation(Request $request, ProjectSetting $project)
+    {
+        $request->validate(['name' => 'required|string|max:255']);
+        $project->locations()->create(['name' => $request->name, 'is_active' => true]);
+        return redirect()->route('settings.projects.index')->with('success', 'Location added.');
+    }
+
+    public function updateLocation(Request $request, ProjectSetting $project, Location $location)
+    {
+        $request->validate(['name' => 'required|string|max:255']);
+        $location->update([
+            'name'      => $request->name,
+            'is_active' => $request->boolean('is_active', true),
+        ]);
+        return redirect()->route('settings.projects.index')->with('success', 'Location updated.');
+    }
+
+    public function destroyLocation(ProjectSetting $project, Location $location)
+    {
+        $location->delete();
+        return redirect()->route('settings.projects.index')->with('success', 'Location deleted.');
+    }
 }