feat(base): enforce unique property names per base

apps/server/src/database/migrations/20260424T120000-base-properties-name-unique.ts

@@ -0,0 +1,20 @@
+import { type Kysely, sql } from "kysely";
+
+/*
+ * Enforce one property name per base (case-insensitive, excluding soft-deleted).
+ * Formulas reference properties by name via `prop("Name")`, and the resolver
+ * builds a `Map<name, id>` — duplicates would silently clobber and make
+ * references non-deterministic. Belt-and-suspenders against races that slip
+ * past service-layer validation.
+ */
+export async function up(db: Kysely<any>): Promise<void> {
+  await sql`
+    CREATE UNIQUE INDEX base_properties_name_unique
+    ON base_properties (base_id, lower(name))
+    WHERE deleted_at IS NULL
+  `.execute(db);
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await sql`DROP INDEX IF EXISTS base_properties_name_unique`.execute(db);
+}