#209 - Add generic socket setsockopt API

[cliffburdick]

For users wanting to customize the socket options for stream_type: socket, add an API to allow them to do so. Pass through the options to Linux.

[greptile-apps]

Greptile Summary

Adds socket_setsockopt(conn_id, level, optname, optval, optlen) — a runtime passthrough to Linux setsockopt for TCP/UDP socket connections, deliberately skipping any YAML option-name mapping layer. The feature threads cleanly through the existing Engine vtable, with a NOT_SUPPORTED base-class default so non-socket engines require no changes.

• C++ API (include/daqiri/common.h, src/common.cpp, src/engine.h/cpp): New public free-function dispatches via g_daqiri_engine->socket_setsockopt(); base class logs CRITICAL and returns NOT_SUPPORTED for engines that don't implement it.
• Socket engine (src/engines/socket/daqiri_socket_engine.cpp): Full implementation with RoCE guard, null-optval check, shared_ptr connection lookup under state_mutex_, and ::setsockopt passthrough. A new private helper apply_socket_int_option consolidates the repeated int-valued setup calls (SO_REUSEADDR, TCP_NODELAY) that previously used bare ::setsockopt with silently ignored return values.
• Python bindings (python/daqiri_common_pybind.cpp): Shim dispatches bool, int, str, bytes, and buffer-protocol objects; GIL is released before each C call and reacquired (via RAII) before any Python-heap cleanup, preserving correct destruction order.
• Docs (AGENTS.md, README.md, all relevant docs/): Updated across every doc-sync target.

Confidence Score: 5/5

Safe to merge — the change is a clean vtable extension with no impact on non-socket engines and no modifications to the BurstParams or burst-free paths.

The new code touches only the socket engine and a new vtable slot. All doc-sync targets are updated, both commits carry DCO sign-offs, and the previous reviewer feedback has been incorporated. The Python shim handles GIL/lifetime ordering correctly across all value types, and the C++ implementation follows every established pattern in the socket engine for mutex-protected connection lookup.

No files require special attention.

Important Files Changed

Filename	Overview
src/engines/socket/daqiri_socket_engine.cpp	Implements socket_setsockopt with RoCE guard, null-optval validation, shared_ptr lookup under mutex, and ::setsockopt passthrough. Also introduces apply_socket_int_option helper that consolidates repeated int-valued setup calls.
python/daqiri_common_pybind.cpp	Python shim correctly dispatches bool, int, str, bytes, and buffer-protocol objects, each releasing the GIL before the C call. Bool check precedes int check correctly; buffer path destruction order is safe.
include/daqiri/common.h	Adds socket_setsockopt to the public free-function API; signature matches vtable and follows existing socket helper conventions.
src/engine.h	Virtual method added to Engine base class; default implementation returns NOT_SUPPORTED, so non-socket engines degrade gracefully.
src/common.cpp	Thin forwarding function follows established pattern: guards with ASSERT_DAQIRI_ENGINE_INITIALIZED(), dispatches through g_daqiri_engine vtable.
src/engine.cpp	Default socket_setsockopt logs CRITICAL and returns NOT_SUPPORTED, matching the style of other unimplemented socket helpers.
src/engines/socket/daqiri_socket_engine.h	Declares socket_setsockopt override and the private apply_socket_int_option helper; consistent with the implementation file.

_{Reviews (2): Last reviewed commit: "#209 - Address Greptile socket API feedb..." | Re-trigger Greptile}