feat: add token usage tracking and leaderboard

- Add token_usage table with composite unique index for claw_id + date
- Add API endpoints: POST /token, GET /token/leaderboard, GET /token/stats
- Add TokenLeaderboard component with daily/total period toggle
- Add CLI commands: `token` and `stats` for reporting and viewing usage
- Add Redis caching for leaderboard with 1-minute TTL
- Add shared utilities: authenticateRequest, getTodayDateString
- Use UPSERT pattern for atomic token updates
- Add i18n translations (en/zh) for new UI elements

lib/db/schema.ts

@@ -7,6 +7,7 @@ import {
   datetime,
   json,
   index,
+  uniqueIndex,
 } from "drizzle-orm/mysql-core";
 import { sql } from "drizzle-orm";
 
@@ -70,3 +71,21 @@ export const geoCache = mysqlTable("geo_cache", {
   region: varchar("region", { length: 50 }),
   updatedAt: datetime("updated_at").default(sql`NOW()`),
 });
+
+export const tokenUsage = mysqlTable(
+  "token_usage",
+  {
+    id: bigint("id", { mode: "number" }).primaryKey().autoincrement(),
+    clawId: varchar("claw_id", { length: 21 }).notNull(),
+    date: varchar("date", { length: 10 }).notNull(), // YYYY-MM-DD
+    inputTokens: bigint("input_tokens", { mode: "number" }).notNull().default(0),
+    outputTokens: bigint("output_tokens", { mode: "number" }).notNull().default(0),
+    createdAt: datetime("created_at").default(sql`NOW()`),
+    updatedAt: datetime("updated_at").default(sql`NOW()`),
+  },
+  (table) => [
+    index("token_usage_claw_id_idx").on(table.clawId),
+    index("token_usage_date_idx").on(table.date),
+    uniqueIndex("token_usage_claw_date_unq").on(table.clawId, table.date),
+  ]
+);