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

app/api/v1/token/route.ts

@@ -0,0 +1,55 @@
+import { NextRequest, NextResponse } from "next/server";
+import { sql } from "drizzle-orm";
+import { db } from "@/lib/db";
+import { invalidateTokenLeaderboardCache } from "@/lib/redis";
+import { authenticateRequest, getTodayDateString } from "@/lib/utils";
+import { tokenSchema } from "@/lib/validators/schemas";
+
+export async function POST(req: NextRequest) {
+  try {
+    const auth = await authenticateRequest(req);
+    if (auth instanceof NextResponse) {
+      return auth;
+    }
+    const { claw } = auth;
+
+    const body = await req.json();
+    const parsed = tokenSchema.safeParse(body);
+    if (!parsed.success) {
+      return NextResponse.json(
+        { error: "Validation failed", details: parsed.error.flatten() },
+        { status: 400 }
+      );
+    }
+
+    const { inputTokens, outputTokens, date } = parsed.data;
+    const targetDate = date || getTodayDateString();
+
+    // Use UPSERT (INSERT ... ON DUPLICATE KEY UPDATE) for atomic operation
+    await db.execute(sql`
+      INSERT INTO token_usage (claw_id, date, input_tokens, output_tokens)
+      VALUES (${claw.id}, ${targetDate}, ${inputTokens}, ${outputTokens})
+      ON DUPLICATE KEY UPDATE
+        input_tokens = ${inputTokens},
+        output_tokens = ${outputTokens},
+        updated_at = NOW()
+    `);
+
+    // Invalidate leaderboard cache
+    await invalidateTokenLeaderboardCache();
+
+    return NextResponse.json({
+      ok: true,
+      date: targetDate,
+      inputTokens,
+      outputTokens,
+      totalTokens: inputTokens + outputTokens,
+    });
+  } catch (error) {
+    console.error("Token report error:", error);
+    return NextResponse.json(
+      { error: "Internal server error" },
+      { status: 500 }
+    );
+  }
+}