feat: add ownerId to Organization and update related database queries; enhance CORS middleware for origin validation

go_cloud/migrations/0004_org_owner_slug.sql

@@ -0,0 +1,28 @@
+-- Scope organization slugs per owner instead of globally unique
+ALTER TABLE organizations ADD COLUMN owner_id UUID REFERENCES users(id);
+
+WITH first_owner AS (
+    SELECT DISTINCT ON (org_id) org_id, user_id
+    FROM memberships
+    WHERE role = 'owner'
+    ORDER BY org_id, created_at
+)
+UPDATE organizations o
+SET owner_id = fo.user_id
+FROM first_owner fo
+WHERE o.id = fo.org_id;
+
+WITH first_member AS (
+    SELECT DISTINCT ON (org_id) org_id, user_id
+    FROM memberships
+    ORDER BY org_id, created_at
+)
+UPDATE organizations o
+SET owner_id = fm.user_id
+FROM first_member fm
+WHERE o.owner_id IS NULL
+  AND o.id = fm.org_id;
+
+ALTER TABLE organizations ALTER COLUMN owner_id SET NOT NULL;
+ALTER TABLE organizations DROP CONSTRAINT organizations_slug_key;
+CREATE UNIQUE INDEX organizations_owner_slug_key ON organizations(owner_id, slug);