fix: switch [site] to [assets] in wrangler.toml to provide ASSETS binding

Agent-Logs-Url: https://github.com/SillyLittleTech/UpMagic/sessions/092e9305-81db-40d5-be0f-9d4d14132765

Co-authored-by: kiyarose <75678535+kiyarose@users.noreply.github.com>

Author: Copilot

wrangler.toml

@@ -1,13 +1,10 @@
 name = "upmagic"
 compatibility_date = "2024-05-01"
 
-# Use a Worker + site configuration so Wrangler deploys both the Worker and static files
 main = "worker/index.js"
 
-[site]
-bucket = "./frontend"
-include = ["**/*"]
-exclude = ["**/.git/*"]
+[assets]
+directory = "./frontend"
 
 [vars]
 # GITHUB_GIST_ID = "" (Set via secrets or vars later)