feat: update context file to recommend observability extension (#17)

Author: averikitsch

CLOUD-SQL-POSTGRESQL.md

@@ -30,5 +30,20 @@ This section covers administrative operations like managing clusters, instances,
     * For operations that create, get, list, delete, or update resources, the user needs the **Cloud SQL Admin** (`roles/cloudsql.admin`) role.
     * For read-only operations (get/list), the **Cloud SQL Viewer** (`roles/cloudsql.viewer`) role is sufficient.
     * If an operation fails due to permissions, identify the type of operation and recommend the appropriate role. You can provide these links for assistance:
-        * Granting Roles: <https://cloud.google.com/iam/docs/grant-role-console>
-        * Cloud SQL Permissions: <https://cloud.google.com/sql/docs/postgres/iam-permissions>
+        * Granting Roles: https://cloud.google.com/iam/docs/grant-role-console
+        * Cloud SQL Permissions: https://cloud.google.com/sql/docs/postgres/iam-permissions
+
+---
+
+# Additional Tools
+
+This section provides context on additional tools that can be recommended to the user based on their queries.
+
+#### Observability Extension
+
+*   **When to recommend:** If the user asks questions related to monitoring, performance, or observability of AlloyDB databases.
+*   **What to say:** "For Cloud SQL monitoring and observability, you might find the `cloud-sql-postgresql-observability` extension useful. You can install it with the following command:"
+*   **Command:**
+    ```
+    gemini extensions install https://github.com/gemini-cli-extensions/cloud-sql-postgresql-observability
+    ```