docs: Update constraint management description to include PRIMARY KEY

- Update features.json description to reflect PRIMARY KEY support
- Address code review feedback

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

src/config/features.json

@@ -89,7 +89,7 @@
     {
       "id": "constraint-management",
       "name": "Constraint Management",
-      "description": "Add and manage table constraints (UNIQUE, CHECK)",
+      "description": "Add and manage table constraints (PRIMARY KEY, UNIQUE, CHECK)",
       "enabled": true,
       "priority": "high",
       "endpoints": [