fix(P1): use #!/bin/sh not bash — runner uses dash as /bin/sh

The Gitea Actions runner (ubuntu-latest) uses dash as /bin/sh. The
previous script used #!/bin/bash with 'set -uo pipefail' — pipefail is
bash-only and causes 'set: illegal option -o pipefail' (exit 2) in dash.
This was the root cause of the build job failing in 2 seconds.

Fix: #!/bin/sh with 'set -u' only (no pipefail). Removed bash-only
features. The script is POSIX-compliant.

---ci---
project: orca
phase: 1
milestone: v0.16
status: execute
---/ci---

scripts/ci-run.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 # ci-run.sh — CoreCI pipeline runner for orca.
 # Called by .coreci.yml jobs via: sh scripts/ci-run.sh <job-name>
 #
@@ -10,8 +10,11 @@
 #   CI_COMMIT_BRANCH — tag name on tag pushes (from GITHUB_REF_NAME)
 #   CI_COMMIT_SHA    — commit SHA
 #   GITEA_TOKEN      — Gitea API token (from Gitea Actions secret PAT_TOKEN)
+#
+# NOTE: uses #!/bin/sh — do NOT use bash-only features (pipefail, [[ ]], etc.)
+# The Gitea Actions runner uses dash as /bin/sh.
 
-set -uo pipefail
+set -u
 
 JOB="${1:-}"
 if [ -z "$JOB" ]; then