v2: fail (exit 1) on naming violation

The four wired repos flip the naming job to a required status check
(agenthub#557 WS6); a check that always exits 0 can never gate. v2 makes
the script exit nonzero with FAIL lines; warn-only stays available via
job-level continue-on-error or the legacy @v1 tag. dfritz break-glass
exemption unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/run

@@ -7,22 +7,16 @@ PASS=0
 FAIL=0
 
 check() {
-  local desc="$1" want_warn="$2" branch="$3" title="$4" author="$5"
+  local desc="$1" want_fail="$2" branch="$3" title="$4" author="$5"
   local out rc=0
   out=$(HEAD_BRANCH="$branch" PR_TITLE="$title" PR_AUTHOR="$author" bash "$SCRIPT" 2>&1) || rc=$?
-  if [ "$rc" -ne 0 ]; then
-    echo "FAIL [$desc]: script exited $rc (must always exit 0)"
-    echo "  output: $out"
-    FAIL=$((FAIL + 1))
-    return
-  fi
-  local got_warn=0
-  echo "$out" | grep -qE "^WARN" && got_warn=1 || true
-  if [ "$got_warn" -eq "$want_warn" ]; then
+  local got_lines=0
+  echo "$out" | grep -qE "^FAIL" && got_lines=1 || true
+  if [ "$rc" -eq "$want_fail" ] && [ "$got_lines" -eq "$want_fail" ]; then
     echo "PASS [$desc]"
     PASS=$((PASS + 1))
   else
-    echo "FAIL [$desc]: expected warn=$want_warn got=$got_warn"
+    echo "FAIL [$desc]: expected exit=$want_fail fail-lines=$want_fail, got exit=$rc fail-lines=$got_lines"
     echo "  output: $out"
     FAIL=$((FAIL + 1))
   fi
@@ -45,16 +39,16 @@ check "support/bug matching title"      0 "support/bug-sup9/clarify-error"
 check "chore — no title prefix"         0 "chore/bump-deps"   "Bump dependency versions"  "dev"
 check "chore — plain title"             0 "chore/fix-a-typo"  "Fix typo in README"         "ops"
 
-# warn: role/bug branch but no [bug-id] title prefix
+# fail: role/bug branch but no [bug-id] title prefix
 check "role/bug no title prefix"        1 "dev/bug-x7k2m9/fix-resize"     "Fix resize"                  "dev"
 
-# warn: bug-id mismatch between branch and title
+# fail: bug-id mismatch between branch and title
 check "bug-id mismatch"                 1 "dev/bug-x7k2m9/fix-resize"     "[bug-zzzzz1] Fix resize"     "dev"
 
-# warn: chore branch with [bug-id] title prefix
+# fail: chore branch with [bug-id] title prefix
 check "chore with bug-id title"         1 "chore/bump-deps"                "[bug-abc123] Bump deps"      "dev"
 
-# warn: invalid branch forms
+# fail: invalid branch forms
 check "invalid — no role prefix"        1 "feature/foo-bar"                "Add feature"                 "dev"
 check "invalid — missing bug segment"   1 "dev/fix-something"              "Fix something"               "dev"
 check "invalid — unknown role"          1 "unknown/bug-abc/thing"          "[bug-abc] Thing"             "dev"