refactor: Replace Map<String, Object> with CallToolRequest in StructuredOutputCallToolHandler

Follow up to #357 to update tool call handler signature from Map<String, Object>
to McpSchema.CallToolRequest for consistency with changes in #375.

- Change BiFunction parameter from Map<String, Object> to McpSchema.CallToolRequest for better type safety
- Update method signature to accept CallToolRequest instead of raw arguments map
- Replace toolSpecification.call() with toolSpecification.callHandler()
- Migrate to builder pattern for AsyncToolSpecification construction

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>