feat(auth): add API key authentication to /token endpoint

Add apiKeyAuth middleware to /token GET endpoint for consistency
with other protected endpoints. Supports both OpenAI (Authorization: Bearer)
and Anthropic (x-api-key) authentication formats.

Author: sachnun

src/routes/token/route.ts

@@ -1,10 +1,11 @@
 import { Hono } from "hono"
 
 import { state } from "~/lib/state"
+import { apiKeyAuth } from "~/middleware/auth"
 
 export const tokenRoute = new Hono()
 
-tokenRoute.get("/", (c) => {
+tokenRoute.get("/", apiKeyAuth, (c) => {
   try {
     return c.json({
       token: state.copilotToken,