Add subject table to core schema

Author: RhysSullivan

apps/cloud/drizzle/0012_woozy_shiva.sql

@@ -0,0 +1,10 @@
+CREATE TABLE "subject" (
+	"external_id" varchar(255) NOT NULL,
+	"created_at" timestamp NOT NULL,
+	"last_seen_at" bigint,
+	"status" text,
+	"row_id" varchar(255) PRIMARY KEY NOT NULL,
+	"tenant" varchar(255) NOT NULL
+);
+--> statement-breakpoint
+CREATE UNIQUE INDEX "subject_uidx" ON "subject" USING btree ("tenant","external_id");