feat: move departments from projects to companies

Departments now belong to a Company, not a Project.
- New migration: recreates settings_departments with company_id (migrates existing data)
- Department model: company_id FK, company() relation
- Company model: departments() hasMany relation
- ProjectSetting model: removes departments() relation
- Controller: dept methods now take Company instead of ProjectSetting
- Routes: department CRUD moves to companies/{company}/departments
- View: departments section appears on each company card (purple theme);
  project body is now locations-only (single column)

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

app/Models/Settings/Department.php

@@ -8,12 +8,12 @@ class Department extends Model
 {
     protected $table = 'settings_departments';
 
-    protected $fillable = ['name', 'project_id', 'is_active'];
+    protected $fillable = ['name', 'company_id', 'is_active'];
 
     protected $casts = ['is_active' => 'boolean'];
 
-    public function project(): \Illuminate\Database\Eloquent\Relations\BelongsTo
+    public function company(): \Illuminate\Database\Eloquent\Relations\BelongsTo
     {
-        return $this->belongsTo(ProjectSetting::class, 'project_id');
+        return $this->belongsTo(Company::class, 'company_id');
     }
 }