fix(check-naming): print corrected title on missing-prefix failure

When a role-bug branch has no [bug-id] prefix in the PR title, the check
now prints what the title should be:

  FAIL[check-naming]: title must lead with [bug-r095xkfgt2vz]
    have: fix(agenthub/bugs): budget unpark quote in bytes not runes
    want: [bug-r095xkfgt2vz] fix(agenthub/bugs): budget unpark quote in bytes not runes

The bug id is already parsed from the branch, so the corrected title is
mechanically derivable — no guesswork needed from the author.

Part of bug-hvhthrwf9ry8

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

check.sh

@@ -41,7 +41,9 @@ fi
 
 if [ "${BRANCH_KIND}" = "role-bug" ]; then
   if [ -z "${TITLE_BUG}" ]; then
-    echo "FAIL[check-naming]: title missing [${BRANCH_BUG}] prefix for branch '${BRANCH}'"
+    echo "FAIL[check-naming]: title must lead with [${BRANCH_BUG}]"
+    echo "  have: ${TITLE}"
+    echo "  want: [${BRANCH_BUG}] ${TITLE}"
     FAILED=1
   elif [ "${TITLE_BUG}" != "${BRANCH_BUG}" ]; then
     echo "FAIL[check-naming]: bug-id mismatch — branch carries '${BRANCH_BUG}' but title carries '${TITLE_BUG}'"