Turbopack failed with "the name HARD_COMPAT_REASONS is defined multiple
times" — two top-level const declarations of the same name existed in
comboStructure.ts. The unused one (with an extra "output_tokens" entry,
zero references anywhere) was dead weight left over from upstream;
the active one (tools/vision/structured_output, used by
hasHardCapabilityFailure/describeCapabilityFilterExhaustion/
filterTargetsByRequestCompatibility) is unaffected.
Confirmed pre-existing on upstream/release/v3.8.50's own tip before
this branch's merge (git show 7f36b192f already has both), so this is
an inherited base-red fix, not new behavior.
⚠️ base-red inherited: #9298
0548f117f1