perf(api): Add collapse=organization to project details endpoint

The project details endpoint serializes the full organization through
OrganizationSummarySerializer which fetches avatars, auth provider
config, and computes feature flags. When the caller only needs the org
id and slug, `?collapse=organization` skips all of that and returns a
minimal object.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: scttcper

src/sentry/api/serializers/models/project.py

@@ -75,6 +75,7 @@
 
 LATEST_DEPLOYS_KEY: Final = "latestDeploys"
 UNUSED_ON_FRONTEND_FEATURES: Final = "unusedFeatures"
+ORGANIZATION_KEY: Final = "organization"
 
 
 # These features are not used on the frontend,
@@ -979,7 +980,16 @@ def get_attrs(
         for option in queryset.iterator():
             options_by_project[option.project_id][option.key] = option.value
 
-        orgs = {d["id"]: d for d in serialize(list({i.organization for i in item_list}), user)}
+        if self._collapse(ORGANIZATION_KEY):
+            orgs = {
+                str(i.organization_id): {
+                    "id": str(i.organization_id),
+                    "slug": i.organization.slug,
+                }
+                for i in item_list
+            }
+        else:
+            orgs = {d["id"]: d for d in serialize(list({i.organization for i in item_list}), user)}
 
         # Only fetch the latest release version key for each project to cut down on response size
         latest_release_versions = _get_project_to_release_version_mapping(item_list)

src/sentry/core/endpoints/project_details.py

@@ -549,7 +549,8 @@ def get(self, request: Request, project: Project) -> Response:
         """
         Return details on an individual project.
         """
-        data = serialize(project, request.user, DetailedProjectSerializer())
+        collapse = request.GET.getlist("collapse", [])
+        data = serialize(project, request.user, DetailedProjectSerializer(collapse=collapse))
 
         # TODO: should switch to expand and move logic into the serializer
         include = set(filter(bool, request.GET.get("include", "").split(",")))

tests/sentry/core/endpoints/test_project_details.py

@@ -115,6 +115,17 @@ def test_no_alert_integration(self) -> None:
         )
         assert not response.data["hasAlertIntegrationInstalled"]
 
+    def test_collapse_organization(self) -> None:
+        response = self.get_success_response(
+            self.project.organization.slug,
+            self.project.slug,
+            qs_params={"collapse": ["organization"]},
+        )
+        assert response.data["organization"] == {
+            "id": str(self.project.organization.id),
+            "slug": self.project.organization.slug,
+        }
+
     def test_filters_disabled_plugins(self) -> None:
         from sentry.plugins.base import plugins