test(sdk): expand Send bound stress test with macro-generated complexity

Extend rs-sdk-send-test with macro-generated deep fetch functions
(up to 50 Fetch call pairs), wrapper chain nesting (3 levels), and
a 16-arm dispatch mirroring dash-evo-tool's real AppContext pattern.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: lklimek