test(evals): copy threshold resolver dependency

The isolated eval-runner fixtures copied the threshold checker without the fixture resolver it now imports, so valid runner scenarios failed before threshold evaluation. Mirroring the runtime-relative layout keeps those black-box fixtures representative of the real runner.

Author: jwilger

scripts/tests/evals-run.bats

@@ -14,7 +14,12 @@ setup() {
 
 copy_eval_runner() {
   destination="$1"
+  fixture_root="$(cd "${destination%/*}/../.." && pwd)"
   cp "$RUNNER" "$destination"
+  mkdir -p "$fixture_root/evals/promptfoo"
+  cp \
+    "$ROOT/evals/promptfoo/fixtures.cjs" \
+    "$fixture_root/evals/promptfoo/fixtures.cjs"
   cp \
     "$ROOT/scripts/evals/provider-compositions.mjs" \
     "${destination%/*}/provider-compositions.mjs"