test(bench): calibrate Session corpus budgets on hosted CI

Standard two-CPU hosted runs are 2.4-3.4 times the reference machine, above
the shared reference scale, so the budgets use rounded hosted medians with
the shared 1.25 headroom. The benchmark job took 14.4 minutes with these
cases; its timeout becomes 25 minutes.

.github/workflows/ci.yml

@@ -196,7 +196,7 @@ jobs:
     name: node 24 / benchmarks
     # Wall-clock budgets need an otherwise idle runner, so this job runs the
     # benchmark lane alone instead of joining a concurrent gate aggregate.
-    timeout-minutes: 30
+    timeout-minutes: 25
     steps:
       - uses: actions/checkout@v6
         with: