ci: disable fullyparallel for binary parameters job (#35995)

Binary parameters tests run unsharded on a single runner. With
fullyparallel enabled, all ~755 api4 tests run concurrently, causing
resource exhaustion (too many server instances, WebSocket hubs, and DB
connections). The test binary gets killed after 11 minutes with no
individual test failures — just overwhelmed resources.

Disabling fullyparallel for this specific job lets binary parameters
tests pass while we evaluate moving them to a nightly/weekly schedule.

Co-authored-by: Claude <claude@anthropic.com>

.github/workflows/server-ci.yml

@@ -208,6 +208,7 @@ jobs:
       logsartifact: postgres-binary-server-test-logs
       go-version: ${{ needs.go.outputs.version }}
       fips-enabled: false
+      fullyparallel: false
   # -- Sharded into 4 parallel runners for ~88% wall-time improvement --
   test-postgres-normal:
     name: Postgres (shard ${{ matrix.shard }})