diff --git a/backend/tools/seed.py b/backend/tools/seed.py
index 5f8912a..08ba223 100644
--- a/backend/tools/seed.py
+++ b/backend/tools/seed.py
@@ -212,6 +212,18 @@ async def run() -> None:
             "category_reference_units, unit_conversions, standard_conversions "
             "RESTART IDENTITY CASCADE"
         ))
+        # Only the 8 canonical topic categories may exist — any leftover slug
+        # (e.g. «سیم», «کابل» from earlier testing) is removed so the topic
+        # grids keep showing exactly the same 8 categories as always.
+        await db.execute(
+            text(
+                "DELETE FROM material_categories WHERE slug NOT IN ("
+                "'mechanical-installations-pipes','electrical-equipment-supplies',"
+                "'doors-windows-glass','metals-steel-sections','construction-materials',"
+                "'construction-chemicals','finishing-interior-decoration',"
+                "'construction-tools-equipment')"
+            )
+        )
 
         # ---- users (roles bound to Casdoor identities by username) ----
         users: dict[str, User] = {}
diff --git a/backups/procurement.dump b/backups/procurement.dump
index f5368d8..bb91e73 100644
Binary files a/backups/procurement.dump and b/backups/procurement.dump differ