conjurer: bump librarian memory limit 1Gi -> 2Gi (headroom)

The work-queue OOM is fixed in code (bounded queue), but a deep search
still loads up to 15000 Crossref records and the accumulating result
JSONs into RAM. Give 2Gi of headroom so a big search isn't OOM-killed;
raise the request to 512Mi to match its real baseline.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

conjurer/librarian.yaml

@@ -33,8 +33,12 @@ spec:
             - { name: doi,   mountPath: /doi, readOnly: true }
             - { name: state, mountPath: /lib_temp_files }
           resources:
-            requests: { cpu: "100m", memory: "256Mi" }
-            limits:   { cpu: "1",    memory: "1Gi" }
+            requests: { cpu: "100m", memory: "512Mi" }
+            # Headroom bump: the work-queue OOM is fixed in code, but a deep
+            # search still pulls up to 15000 Crossref records into RAM and the
+            # accumulating result JSONs are loaded whole. 2Gi gives margin so a
+            # big search isn't OOM-killed. Tune down if the node is tight.
+            limits:   { cpu: "1",    memory: "2Gi" }
       volumes:
         - name: doi
           nfs: