feat: add independent LLMConfig permissions for AI profile management

Add new privilege definitions:
- LLMConfig.Audit - View LLM model configurations
- LLMConfig.Modify - Update LLM model configurations
- LLMConfig.Allocate - Create/delete LLM model configurations

Add LLMConfig.Audit and LLMConfig.Modify to default User role so that
regular users can manage their own AI profiles without needing the
User.Manager role.

User-scoped LLM config endpoints now use LLMConfig.* permissions.
Group-scoped LLM config endpoints retain Group.* permissions.

gns3server/db/models/privileges.py

@@ -226,6 +226,18 @@ def create_default_roles(target, connection, **kw):
         {
             "description": "View an appliance",
             "name": "Appliance.Audit"
+        },
+        {
+            "description": "Create or delete an LLM model configuration",
+            "name": "LLMConfig.Allocate"
+        },
+        {
+            "description": "View an LLM model configuration",
+            "name": "LLMConfig.Audit"
+        },
+        {
+            "description": "Update an LLM model configuration",
+            "name": "LLMConfig.Modify"
         }
     ]
 
@@ -295,7 +307,9 @@ def add_privileges_to_default_roles(target, connection, **kw):
         "Image.Audit",
         "Compute.Audit",
         "Appliance.Allocate",
-        "Appliance.Audit"
+        "Appliance.Audit",
+        "LLMConfig.Audit",
+        "LLMConfig.Modify"
     )
 
     add_privileges_to_role(target, connection, "User", user_privileges)