chore: prune dead vars from turbo.json globalEnv

SENTRY_PROJECT_WEB_TANSTACK and VERCEL_ENV have zero consumers in the
tree (web-tanstack has no sentry upload config; nothing reads
VERCEL_ENV), so they only widened the global cache key. The other
Sentry/Vercel vars stay — next.config.mjs and init paths read them. (S9)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

turbo.json

@@ -17,12 +17,10 @@
     "SENTRY_ORG",
     "SENTRY_PROJECT_WEB_NEXT",
     "SENTRY_PROJECT_CMS",
-    "SENTRY_PROJECT_WEB_TANSTACK",
     "SENTRY_TRACES_SAMPLE_RATE",
     "SENTRY_ENVIRONMENT",
     "VERCEL_GIT_COMMIT_SHA",
     "NEXT_PUBLIC_VERCEL_GIT_COMMIT_SHA",
-    "VERCEL_ENV",
     "AUDIT_PSEUDONYM_SALT"
   ],
   "boundaries": {