Remove Prettier from the repo (#1980)

Prettier has been disabled since we migrated to Mintlify because it was
breaking lots of stuff. I spent some time last week (#1978) trying to
make it play nice with our content but the juice just ain't worth the
squeeze. It would clean up 500 files and absolutely slaughter another
500. I even tried writing custom scripts to override the stuff Prettier
would do wrong but it was way too janky. Not worth it! So let's get rid
of it.

Author: sg-writer

.github/workflows/ci-checks.yml

@@ -19,5 +19,3 @@ jobs:
           echo DEPLOY_ENV=dev > .env
       - name: Install Dependencies 📥
         run: pnpm install --frozen-lockfile
-      - name: Fmt Check 🧹
-        run: pnpm run fmt:check

.prettierignore

@@ -5,8 +5,6 @@
   "main": "index.js",
   "scripts": {
     "dev": "mint dev --port 3333",
-    "fmt:check": "biome check . --diagnostic-level=error && prettier --check .",
-    "fmt": "biome check . --write --diagnostic-level=error --organize-imports-enabled=true && prettier --write .",
     "check-redirect-conflicts": "node custom/scripts/check-redirect-conflicts.js",
     "test-links": "mint broken-links",
     "vale": "vale --glob='!{snippets/**,errors/**,.skills/**,agent/cli-api.mdx,agent/cli.mdx,style-guide.mdx}' .",
@@ -21,12 +19,10 @@
     "@babel/traverse": "^7.28.4",
     "@ngrok/mantle": "^0.52.9",
     "@types/react": "^19.1.13",
-    "biome": "^0.3.3",
     "gray-matter": "^4.0.3",
     "js-yaml": "^4.1.0",
     "mint": "^4.2.176",
     "mdx2vast": "^0.3.0",
-    "prettier": "^3.6.2",
     "react": "^19.1.1",
     "react-markdown": "^10.1.0"
   }