fix: update apm-v4 submodule (193→14 test failures resolved)

GenServerHelpers.ensure_processes_alive() added to 15 test setup blocks.
398 tests, 14 remaining failures (11 ExportManager supervisor conflicts,
2 ApiController ArgumentError, 1 DashboardLive CSS assertion).

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

Author: peguesj