ci: fix boj-build secrets-in-if + Scorecard enforcer

boj-build.yml: removed the job-level `if:` referencing secrets.BOJ_SERVER_URL.
The `secrets` context is not available in `if:` — referencing it invalidates
the whole workflow. The trigger step already shell-guards on an empty BOJ_URL
and exits 0, so an unconfigured repo stays a fast no-op (honouring the
documented secret-or-var configuration).

scorecard-enforcer.yml: the scorecard job invoked ossf/scorecard-action with
publish_results: true AND a run: step in the same job, which OSSF rejects with
HTTP 400 ("scorecard job must only have steps with `uses`"), failing the run.
Split into an uses-only publish job + an unprivileged JSON score-gate (reads
top-level `.score`; the SARIF aggregate path is absent so the old gate always
read 0 and failed < 5). Least-privilege contents:read, timeouts, SHA pins.

https://claude.ai/code/session_01VwbFNQJw23tW8tqM7utWku

Author: claude

.github/workflows/boj-build.yml

@@ -18,7 +18,11 @@ permissions:
 jobs:
   trigger-boj:
     runs-on: ubuntu-latest
-    if: ${{ vars.BOJ_SERVER_URL != '' || secrets.BOJ_SERVER_URL != '' }}
+    # No job-level enablement gate: the `secrets` context is not available in
+    # `if:` (referencing it invalidates the whole workflow), and gating on
+    # `vars` alone would silently drop a secret-only configuration. The
+    # "Trigger BoJ Server" step shell-guards on an empty BOJ_URL and exits 0,
+    # so an unconfigured repo is a fast no-op regardless of secret-or-var.
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

.github/workflows/scorecard-enforcer.yml

@@ -21,8 +21,15 @@ permissions:
   contents: read
 
 jobs:
+  # Publish job. The OSSF attestation flow requires that a job invoking
+  # ossf/scorecard-action with publish_results: true contain ONLY `uses:`
+  # steps (no `run:`). A `run:` step in this job makes the OSSF publish
+  # endpoint reject the upload with HTTP 400 ("scorecard job must only have
+  # steps with `uses`"), failing the whole workflow. Score enforcement is
+  # therefore split into the separate unprivileged `score-gate` job below.
   scorecard:
     runs-on: ubuntu-latest
+    timeout-minutes: 15
     permissions:
       security-events: write
       id-token: write  # For OIDC
@@ -43,10 +50,35 @@ jobs:
         with:
           sarif_file: results.sarif
 
+  # Unprivileged enforcement gate. Re-derives the score read-only (no
+  # publish, no id-token), so it may legally contain a `run:` step.
+  # NOTE: uses JSON output deliberately. The SARIF format does NOT carry the
+  # aggregate score at .runs[0].tool.driver.properties.score (it is absent
+  # there, so a SARIF-based gate reads the `// 0` fallback and ALWAYS fails
+  # the < MIN_SCORE check); the JSON format exposes the aggregate at the
+  # top-level `.score`. publish_results is false here and does not affect the
+  # computed score, so enforcement behaviour is unchanged.
+  score-gate:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+
+      - name: Run Scorecard (analysis only)
+        uses: ossf/scorecard-action@4eaacf0543bb3f2c246792bd56e8cdeffafb205a # v2.4.3
+        with:
+          results_file: results.json
+          results_format: json
+          publish_results: false
+
       - name: Check minimum score
         run: |
-          # Parse score from results
-          SCORE=$(jq -r '.runs[0].tool.driver.properties.score // 0' results.sarif 2>/dev/null || echo "0")
+          # JSON output carries the aggregate score at the top-level `.score`.
+          SCORE=$(jq -r '.score // 0' results.json 2>/dev/null || echo "0")
 
           echo "OpenSSF Scorecard Score: $SCORE"
 
@@ -61,6 +93,7 @@ jobs:
   # Check specific high-priority items
   check-critical:
     runs-on: ubuntu-latest
+    timeout-minutes: 15
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2