Improve SSH key filtering and datalist component

- Add ownedAndOnlySShKeys() method to filter out git-related keys
- Update Boarding component to use new filtering method
- Enhance datalist component with better multi-select and single-select handling
- Fix Alpine.js reactivity and improve UI interactions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/Models/PrivateKey.php

@@ -88,6 +88,16 @@ class PrivateKey extends BaseModel
         return self::whereTeamId($teamId)->select($selectArray->all());
     }
 
+    public static function ownedAndOnlySShKeys(array $select = ['*'])
+    {
+        $teamId = currentTeam()->id;
+        $selectArray = collect($select)->concat(['id']);
+
+        return self::whereTeamId($teamId)
+            ->where('is_git_related', false)
+            ->select($selectArray->all());
+    }
+
     public static function validatePrivateKey($privateKey)
     {
         try {