- workflows.yaml: declare `shared_volume: { mount_path: /workspace,
size: 30Gi }` on the ci workflow so all sub-workflows share a PVC;
set `shell: /bin/bash` on ci_config/ci_long_config anchors.
- log_search.rs: fix opensearch_url() TCP probe to resolve hostnames
(not just IPs); make ensure_index handle resource_already_exists
races gracefully.
- webhook.rs: 14 new handler-level tests covering generic event auth
(accept/reject/missing), GitHub/Gitea HMAC verification, bad JSON
400s, trigger matching, trigger ref-mismatch skip, and real
workflow-start side effect verification.
Pure formatting pass from `cargo fmt --all`. No logic changes. Separating
this out so the 1.9 release feature commits that follow show only their
intentional edits.
