perf(spp_metric_service): address gemini-code-assist review findings

- recordset subtraction instead of lambda filter for individuals
- batch individual ids from memberships (avoids N+1)
- check _fields membership instead of hasattr on recordsets
- early return for falsy raw_value before code search

Author: gonzalesedwin1123

spp_metric_service/models/breakdown_service.py

@@ -122,8 +122,9 @@ def _expand_groups_to_members(self, registrant_ids):
         Partner = self.env["res.partner"].sudo()  # nosemgrep: odoo-sudo-without-context,odoo-sudo-on-sensitive-models
         records = Partner.browse(registrant_ids).exists()
 
-        group_ids = records.filtered("is_group").ids
-        individual_ids = set(records.filtered(lambda r: not r.is_group).ids)
+        groups = records.filtered("is_group")
+        group_ids = groups.ids
+        individual_ids = set((records - groups).ids)
 
         if not group_ids:
             return list(individual_ids)
@@ -137,7 +138,6 @@ def _expand_groups_to_members(self, registrant_ids):
             ]
         )
 
-        for membership in memberships:
-            individual_ids.add(membership.individual.id)
+        individual_ids.update(memberships.individual.ids)
 
         return list(individual_ids)

spp_metric_service/models/demographic_dimension.py

@@ -189,7 +189,7 @@ def _evaluate_field(self, record):
             # Odoo recordset (Many2one). Empty recordset means the field is unset.
             if not value:
                 return self.default_value or "unknown"
-            if hasattr(value, "code") and value.code:
+            if "code" in value._fields and value.code:
                 key = str(value.code)
             else:
                 key = value.display_name or str(value.id)
@@ -266,6 +266,9 @@ def _lookup_m2o_label(self, raw_value):
         :param raw_value: The raw dimension value (typically a code string)
         :returns: display_name or None if not found
         """
+        if not raw_value:
+            return None
+
         # Only handle simple field paths (one segment, no dotted traversal
         # like "gender_id.code" where the user explicitly chose a sub-field)
         if "." in self.field_path: