test/ci: make clojure-test-suite per-file deadline configurable (JOLT_SUITE_TIMEOUT)

The 6s per-file deadline + baseline=3981 were tuned to a fast dev machine; a
slower CI runner could time out a sub-second finite file, dropping total-pass
below baseline and flaking CI red. The deadline is now an env var (default 6
locally); CI sets it to 20s for headroom.

Characterized the 6 timeouts: identical pass/timeout counts at 6s and 20s, so all
6 are genuinely-infinite hangs (killed at any deadline) and the 227 finite files
finish well under 6s. So no baseline margin is needed — a generous CI deadline
removes the flake risk while preserving full regression sensitivity.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/tests.yml

@@ -10,6 +10,11 @@ jobs:
     runs-on: ubuntu-latest
     env:
       JANET_VERSION: v1.41.2   # bump to match the version Jolt is developed against
+      # Per-file deadline for the clojure-test-suite battery. Finite files finish
+      # in well under 1s; the genuinely-infinite ones get killed at any deadline.
+      # A generous value gives slow CI runners headroom so a sub-second file
+      # spiking doesn't time out and drop total-pass below the baseline.
+      JOLT_SUITE_TIMEOUT: "20"
     steps:
       - uses: actions/checkout@v4
         with: