chore(db): regenerate kb→workspace cascade migration as 0243

Regenerated via drizzle-kit generate on top of the merged staging
migrations (staging took 0242). Re-applied the safety edits: NOT VALID
+ separate VALIDATE on the FK re-add, and the -- migration-safe note on
the DROP. check:migrations passes.

Author: icecrasher321

packages/db/migrations/0243_kb_workspace_cascade.sql

@@ -0,0 +1,6 @@
+-- migration-safe: re-creates the existing knowledge_base→workspace FK only to change its ON DELETE action to cascade. The column and FK are otherwise unchanged and the FK is re-added immediately below (atomic within the migration transaction); no app code depends on the FK's delete action.
+ALTER TABLE "knowledge_base" DROP CONSTRAINT "knowledge_base_workspace_id_workspace_id_fk";
+--> statement-breakpoint
+ALTER TABLE "knowledge_base" ADD CONSTRAINT "knowledge_base_workspace_id_workspace_id_fk" FOREIGN KEY ("workspace_id") REFERENCES "public"."workspace"("id") ON DELETE cascade ON UPDATE no action NOT VALID;
+--> statement-breakpoint
+ALTER TABLE "knowledge_base" VALIDATE CONSTRAINT "knowledge_base_workspace_id_workspace_id_fk";