chore: add tools section to librarian.yaml

Author: hj690

librarian.yaml

@@ -18,6 +18,22 @@ sources:
   googleapis:
     commit: fe04226e3d76435acbfd3ffb51f6771740e1fb5b
     sha256: e99c641a9c5525394de43c762b9db50c3ada1f219d6dbdba594ae992fbe1d838
+tools:
+  pip:
+    - name: gapic-generator
+      version: "1.37.1"
+    - name: nox
+      version: "2025.11.12"
+    - name: ruff
+      version: "0.14.14"
+    - name: isort
+      version: "5.11.0"
+    - name: black
+      version: "23.7.0"
+      package: "black[jupyter]==23.7.0"
+    - name: synthtool
+      version: "e643ce8e20f8fe237a31a1754524ba987de72875"
+      package: "gcp-synthtool@git+https://github.com/googleapis/synthtool@e643ce8e20f8fe237a31a1754524ba987de72875"
 default:
   output: packages
   tag_format: '{name}-v{version}'