ci(client): source files may not grow past their size baseline

lint:size counts the lines of every source file under client/src, tests
aside. A file may hold 1000 lines; the 24 files that are longer today are
listed in scripts/size-baseline.json with their current length and fail
the check when they grow. --update lowers an entry once a file shrinks
and never raises one, so a long file is split by concern instead of
growing. A baseline that cannot be read or parsed stops the check with
its reason, and --update leaves it as it is. It runs in the client job
next to the reading direction check.

.github/workflows/test.yml

@@ -241,6 +241,12 @@ jobs:
         # so new code uses the logical start/end forms (scripts/rtl-lint.mjs).
         run: cd client && npm run lint:rtl
 
+      - name: File size check
+        # A source file may hold no more lines than scripts/size-baseline.json
+        # allows (1000 for a file without an entry), so a big file is split by
+        # concern instead of growing (scripts/size-lint.mjs).
+        run: cd client && npm run lint:size
+
   plugin-sdk-quality:
     name: Plugin SDK Types
     runs-on: ubuntu-latest