fix: Update Netlify config to use redirects instead of proxying

- Change status from 200 (proxy) to 301 (redirect) to eliminate bandwidth costs
- Update TinyTorch URL to tinytorch.ai
- Remove cache-bust header (not needed for redirects)

This immediately fixes the high bandwidth usage issue.

netlify.toml

@@ -60,21 +60,20 @@
 
 [[redirects]]
   from = "/tinytorch"
-  to = "https://mlsysbook.github.io/TinyTorch/intro.html"
+  to = "https://tinytorch.ai"
   status = 301
 
 [[redirects]]
   from = "/tinytorch/"
-  to = "https://mlsysbook.github.io/TinyTorch/intro.html"
+  to = "https://tinytorch.ai"
   status = 301
 
-# Proxy all other requests to GitHub Pages with cache-busting
+# Redirect all other requests to GitHub Pages (no proxying = no bandwidth cost!)
 [[redirects]]
   from = "/*"
   to = "https://harvard-edge.github.io/cs249r_book/:splat"
-  status = 200
+  status = 301
   force = true
-  headers = {X-Cache-Bust = "=1"}
 
 # Security and performance headers
 [[headers]]