Tags: vixcpp/async

Merge dev

async: make Asio dependency public

fix(async): stabilize scheduler shutdown and asio net service stop

chore(async): update asio submodule to latest commit

perf(async): optimize coroutine fast-path and remove redundant error …

…helper

- introduce post_handle() fast path across scheduler/io_context
- remove lambda-based coroutine resumption (direct handle posting)
- optimize asio bridge (awaitable, tcp, udp, dns)
- align thread_pool with coroutine fast-path (ctx_post_handle)
- optimize timer and signal wakeups using handle-based resume
- refactor when_all/when_any to use scheduler fast path
- cleanup spawn_detached to avoid lambda overhead
- remove duplicate cancelled_ec() from error.hpp (fix redefinition)
- overall reduction of allocations and indirections in async hot path