chore: remove tokenlens and token usage tracking (#1357)

lib/db/schema.ts

@@ -3,7 +3,6 @@ import {
   boolean,
   foreignKey,
   json,
-  jsonb,
   pgTable,
   primaryKey,
   text,
@@ -11,7 +10,6 @@ import {
   uuid,
   varchar,
 } from "drizzle-orm/pg-core";
-import type { AppUsage } from "../usage";
 
 export const user = pgTable("User", {
   id: uuid("id").primaryKey().notNull().defaultRandom(),
@@ -31,7 +29,6 @@ export const chat = pgTable("Chat", {
   visibility: varchar("visibility", { enum: ["public", "private"] })
     .notNull()
     .default("private"),
-  lastContext: jsonb("lastContext").$type<AppUsage | null>(),
 });
 
 export type Chat = InferSelectModel<typeof chat>;