ci: set SHAPEPIPE_ON_CANDIDE=0 so candide tests reliably skip in CI

conftest's on_candide() matches the hostname against ^(c\d|n\d{2}) and the
comment explicitly says to override it "for CI or odd hostnames" — but the
workflow never did. CI runs pytest via `docker run` with no --hostname, so
the container's hostname is its hex ID; ~4% of the time that ID starts with
c+digit, on_candide() false-positives, the candide-marked cluster tests run
instead of skipping, and they ERROR on the missing candide data
(FileNotFoundError) — a flaky red on an otherwise-green suite (275 passed,
2 should-be-skipped). Set the override the conftest already supports.

(Same one-liner should land on develop; the flake exists there too.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DwHw42NeHoEWwsykwwDooP

Author: cailmdaley

.github/workflows/deploy-image.yml

@@ -123,7 +123,7 @@ jobs:
       - name: Test dev — pytest suite
         run: |
           IMAGE=$(echo "${{ steps.meta-dev.outputs.tags }}" | head -n1)
-          docker run --rm -e HYPOTHESIS_PROFILE=ci "$IMAGE" pytest -rX
+          docker run --rm -e HYPOTHESIS_PROFILE=ci -e SHAPEPIPE_ON_CANDIDE=0 "$IMAGE" pytest -rX
 
       # ----------------------------------------------------------------
       # Publish (push events only — never on pull_request, incl. forks).