deps: bump posthog-telemetry to 4cd2256 (teardown SIGSEGV fix)

The 0433745 pin can SIGSEGV at process exit: its atexit shutdown
handler drains the telemetry queue, constructing new httplib Clients
whose ctor regex (a function-local static, destroyed before the
handler runs) is already dead. Deterministic crash reproduced in
quack-oauth's DuckDB v1.5.3 statically-linked test binary (exit 139
after all tests pass); same mechanism applies to any consumer with
events still queued at exit.

New pin (DataZooDE/posthog-telemetry#4): Stop() discards pending
tasks instead of draining them, and Instance() pre-warms httplib's
statics before registering the atexit handler.

Author: jrosskopf