chore(skills): resync plan-dag — pick up test.sh --stagger=0 fix

Pulls in onsager-ai/onsager-skills@d178bc0 which makes the
`--stagger=0` smoke check actually fail loudly instead of
swallowing the exit code with `|| true`.

Author: claude

.agents/skills/plan-dag/scripts/plan-dag-render.test.sh

@@ -359,14 +359,28 @@ PY
         printf '  FAIL --stagger did not measurably shrink width (%s → %s pt)\n' "$raw_w" "$stag_w"
     fi
 fi
-# --stagger=0 must always produce identical output to the no-unflatten baseline.
+# --stagger=0 must produce a valid PNG (same shape as the happy-path PNG smoke
+# above): capture the exit code, treat a Playwright-skip stderr as skip, and
+# fail loudly for anything else.
 "$SCRIPT" "$FIX/happy.json" --stagger=0 --out "$tmp/stag0.png" \
-    >/dev/null 2>"$tmp/stag0.err" || true
-if grep -qE "$png_skip_re" "$tmp/stag0.err" 2>/dev/null; then
-    printf '  skip --stagger=0 PNG (Playwright/Chromium not available)\n'
-elif [ ! -s "$tmp/stag0.png" ] && [ ! -e "$tmp/stag0.png" ]; then
-    : # nothing to assert
-elif file "$tmp/stag0.png" 2>/dev/null | grep -q 'PNG image'; then
+    >/dev/null 2>"$tmp/stag0.err"
+rc=$?
+if [ "$rc" -ne 0 ]; then
+    if grep -qE "$png_skip_re" "$tmp/stag0.err"; then
+        printf '  skip --stagger=0 PNG (Playwright/Chromium not available)\n'
+    else
+        fail=$((fail + 1))
+        printf '  FAIL --stagger=0 exited %d\n' "$rc"
+        sed 's/^/    /' < "$tmp/stag0.err"
+    fi
+elif [ ! -s "$tmp/stag0.png" ]; then
+    fail=$((fail + 1))
+    printf '  FAIL --stagger=0 produced empty output\n'
+elif ! file "$tmp/stag0.png" 2>/dev/null | grep -q 'PNG image'; then
+    fail=$((fail + 1))
+    printf '  FAIL --stagger=0 output is not a PNG (file: %s)\n' \
+        "$(file "$tmp/stag0.png" 2>/dev/null || echo unknown)"
+else
     pass=$((pass + 1))
     printf '  ok  --stagger=0 renders a PNG\n'
 fi

skills-lock.json

@@ -15,7 +15,7 @@
       "source": "onsager-ai/onsager-skills",
       "sourceType": "github",
       "skillPath": "skills/plan-dag/SKILL.md",
-      "computedHash": "832e649a4efa93b178636a5e11b0cf1fc4441931ab82493baeb87540448e63cc"
+      "computedHash": "203486861e5e1576084b2ec9b73a3b67b8b22d2904516d59477a65c548cf1db5"
     }
   }
 }