build(scripts): server ratchets share one baseline library at the repository root

scripts/lib/ratchet.mjs carries the tree walk, the CRLF-safe reader and the
baseline handling the client ratchets already use, next to a warning tally and
a format comparison that take ESLint and Prettier from the calling workspace.
server lint:size now runs on it with the same messages and exit codes, and the
libraries have node:test suites that CI runs in the server job.

.github/workflows/test.yml

@@ -259,6 +259,11 @@ jobs:
         # wrapped), so a big service is split by concern instead of growing.
         run: cd server && npm run lint:size
 
+      - name: Shared ratchet code
+        # scripts/lib/ at the root holds the baseline handling, the warning
+        # tally and the format comparison the server and shared gates run.
+        run: npm run test:lib-scripts
+
       - name: Import boundaries and cycles
         # No new load-time cycle, no new reach into another domain's
         # internals, src/db stays below src/nest. Today's violations sit in