Replaces blocking pthread_join() per thread with a CLOCK_MONOTONIC
deadline + 5ms poll loop. CONF_PUSH_TIMEOUT_MS (500ms) now enforced.
Matches design §6.3 aggregate timeout guarantee.
- Add done field to push_ctx_t; push_thread sets it on exit
- Add static wait_all_with_timeout() before push_config_to_standbys()
- Wire push_config_to_standbys() to use wait_all_with_timeout()
- Add #include <stdatomic.h> to config_repl.c
- Guard push_ctx_t local typedef with #ifndef XCE_TESTING
- Expose push_ctx_t and wait_all_with_timeout_for_test() in header
under XCE_TESTING for unit test access
- Add test_wait_all_with_timeout_slow_threads (timeout fires, acked=0)
- Add test_wait_all_with_timeout_fast_threads (all complete, acked=3)
- Update design doc §6.3 with actual implementation signature and
5ms poll interval note
load_primary_config() reads from workdir/name/conf — conf_save_config()
was writing to workdir/conf. Latent bug: would have corrupted upgrade
restart cycle once Task 11 wired the upgrade path.
Update all conf_read_current_filename, conf_get_saved_tag, and
conf_check_stale calls in the test suite to use the corrected
effective_dir (workdir/name) path structure. Add new test
test_conf_save_config_path_consistency that explicitly verifies the
written path matches what load_primary_config() reads.
