internal: Use Vercel ignoreCommand to skip unnecessary deploys (#3778)

Replace blanket `deploymentEnabled: false` with an ignoreCommand that
conditionally builds based on what changed:
- master: deploy when website/ or docs/ changed
- other branches: deploy only when website/ changed

Made-with: Cursor

Author: ntucker

website/vercel.json

@@ -1,6 +1,4 @@
 {
   "cleanUrls": true,
-  "git": {
-    "deploymentEnabled": false
-  }
+  "ignoreCommand": "if [ \"$VERCEL_GIT_COMMIT_REF\" = \"master\" ]; then git diff HEAD^ HEAD --quiet -- . ../docs/; else git diff HEAD^ HEAD --quiet -- .; fi"
 }