perf: lazy-load Workspace relationships to reduce N+1 queries

Add explicit $with = [] to prevent any auto-eager-loading of the 30+
relationships defined on the Workspace model. Provide scopeWithCommon()
for eager-loading core tenant relationships (users, members, teams,
workspacePackages, namespaces) and scopeWithCommonCounts() as a lighter
alternative using withCount() for listing pages.

Fixes #21

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Models/Workspace.php

@@ -54,6 +54,17 @@ class Workspace extends Model
 {
     use HasFactory;
 
+    /**
+     * Relationships that should be eager-loaded by default.
+     *
+     * Explicitly empty to prevent N+1 queries when listing workspaces.
+     * Use scopeWithCommon() to eager-load the most frequently needed
+     * relationships, or call ->with() explicitly for specific use cases.
+     *
+     * @var array<int, string>
+     */
+    protected $with = [];
+
     protected static function newFactory(): WorkspaceFactory
     {
         return WorkspaceFactory::new();
@@ -778,6 +789,47 @@ class Workspace extends Model
         return $query->orderBy('sort_order');
     }
 
+    /**
+     * Scope to eager-load the most commonly needed relationships.
+     *
+     * Use this when listing workspaces or rendering dashboards to avoid
+     * N+1 queries. Only loads core tenant relationships that are almost
+     * always needed; module-specific relationships (social, analytics,
+     * trust, notify, commerce, etc.) should be loaded explicitly.
+     *
+     * Example: Workspace::withCommon()->paginate(20)
+     */
+    public function scopeWithCommon($query)
+    {
+        return $query->with([
+            'users',
+            'members',
+            'teams',
+            'workspacePackages',
+            'namespaces',
+        ]);
+    }
+
+    /**
+     * Scope to add commonly needed relationship counts.
+     *
+     * Lighter alternative to withCommon() when only counts are needed
+     * (e.g. admin listing pages). Uses withCount() to add _count
+     * columns without loading full relationship collections.
+     *
+     * Example: Workspace::withCommonCounts()->paginate(20)
+     */
+    public function scopeWithCommonCounts($query)
+    {
+        return $query->withCount([
+            'users',
+            'members',
+            'teams',
+            'workspacePackages',
+            'invitations',
+        ]);
+    }
+
     /**
      * Convert to array format used by WorkspaceService.
      */