fix(db): seed staff_id FK fix (GRO-369)

Fixes staff_id FK violation on re-seed: move TRUNCATE before staff upsert and add id to onConflictDoUpdate set clause.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/migrations/0020_typical_daimon_hellstrom.sql

@@ -0,0 +1,7 @@
+-- Clean up existing duplicate services before adding unique constraint.
+-- Keep the row with the lowest id per name; delete all others.
+DELETE FROM services WHERE id NOT IN (
+  SELECT (MIN(id::text))::uuid FROM services GROUP BY name
+);
+
+ALTER TABLE "services" ADD CONSTRAINT "services_name_unique" UNIQUE("name");