merge: sync Rongsong's scheduler-framework into chatbot

Full merge of origin/scheduler-framework (scheduler-core restructure,
failover-adoption, WAL_JOB_DISPATCH, apiserver backend health/heartbeat,
build-time versioning, bug-1673/1676/1678/1679/1680).

Conflict resolution:
- scheduler: adopt Rongsong's scheduler-core architecture (driver loop,
  queue project/picker fields, resource bug-1569 fix)
- worker/controller_connector.c: keep Rongsong's reconnect/rejoin
  structure, PORT our bug-1509 resend_job_status onto the rejoin success
  path (his reconnect didn't re-report job state)
- apiserver backend: take Rongsong's health/heartbeat (supersedes our
  e505066 circuit breaker)
- group.c: keep our bug-1513 comment
- misc: take theirs for additive fixes (go_build versioning,
  test_group.c, persist.c RUSAGE_UPDATE, FilterRows bug-1680)

NOTE: our scheduler fixes (bug-1494 family dispatch-fail requeue,
PEND-reason classification) are NOT in Rongsong's branch — needs
verification/porting onto scheduler-core (separate follow-up).

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

src/lib/meson.build

@@ -179,6 +179,7 @@ libxce_test_src = ['testsuite/test.c',
                    'testsuite/test_libxce_retry.c',
                    'testsuite/test_netio_on_connected.c',
                    'testsuite/test_netio_on_fini.c',
+                   'testsuite/test_netio_reconnect_gen.c',
                    'testsuite/test_netio_arm_failure.c',
                    'testsuite/test_netio_close_propagation.c',
                    'testsuite/test_netio_bounded_connect.c',