feat(core): add thread files, deleting their blobs with the thread

Author: tjholm

packages/core/drizzle/20261006224734_thread_files/migration.sql

@@ -0,0 +1,33 @@
+CREATE TABLE "blob_deletion" (
+	"id" uuid PRIMARY KEY DEFAULT uuidv7(),
+	"prefix" text NOT NULL,
+	"queued_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE TABLE "thread_file" (
+	"id" uuid PRIMARY KEY DEFAULT uuidv7(),
+	"thread_id" uuid NOT NULL,
+	"tool_call_id" uuid,
+	"content_type" text NOT NULL,
+	"size" integer NOT NULL,
+	"created_at" timestamp with time zone DEFAULT now() NOT NULL
+);
+--> statement-breakpoint
+CREATE INDEX "thread_file_thread_idx" ON "thread_file" ("thread_id");--> statement-breakpoint
+ALTER TABLE "thread_file" ADD CONSTRAINT "thread_file_thread_id_thread_id_fkey" FOREIGN KEY ("thread_id") REFERENCES "thread"("id") ON DELETE CASCADE;--> statement-breakpoint
+ALTER TABLE "thread_file" ADD CONSTRAINT "thread_file_tool_call_id_tool_call_id_fkey" FOREIGN KEY ("tool_call_id") REFERENCES "tool_call"("id") ON DELETE SET NULL;--> statement-breakpoint
+
+-- A thread is deleted by its workspace's, pod's or host agent's cascade as well as directly, and only the database sees every route. Queues the thread's blob folder, `threads/<id>` (see `thread-files.ts`), once per statement however many threads it deleted.
+CREATE FUNCTION queue_deleted_thread_blobs() RETURNS trigger
+LANGUAGE plpgsql AS $$
+BEGIN
+	INSERT INTO "blob_deletion" ("prefix")
+	SELECT 'threads/' || "id"::text FROM deleted_threads;
+	RETURN NULL;
+END;
+$$;--> statement-breakpoint
+
+CREATE TRIGGER thread_blob_deletion
+AFTER DELETE ON "thread"
+REFERENCING OLD TABLE AS deleted_threads
+FOR EACH STATEMENT EXECUTE FUNCTION queue_deleted_thread_blobs();