test(scheduler-core): normal-mode <-> simulation decision equivalence (task 11.6)

Chain the already-shipped recording (task 9.2) and sim-output (tasks
11.1-11.5) pipelines: record a synthetic multi-queue session through the
normal-mode driver, replay it through the simulation driver with
--sim-output, and assert the two .replay files' decisions match in full
structural content. This is the spec's central validation contract (Req 5
AC 7.1) -- if normal and simulation modes diverge, the core/driver
separation is broken.

Honestly scoped to PEND-only decisions: sim_loop.c's picker thread
(task 11.2) has no code path that can emit a live DISPATCH today, a
pre-existing gap that belongs to the not-yet-designed scheduler-allocation
spec, not something this task can close.

src/scheduler/testsuite/meson.build

@@ -610,6 +610,32 @@ sched_sim_record_output_test = executable(
     dependencies: [scheduler_test_deps],
     install: false)
 
+# Contract test for deterministic replay and normal-to-simulation
+# equivalence (scheduler-core spec, task 11.6, Req 5 AC 7.1) -- the spec's
+# own central regression test: a synthetic scheduling session recorded
+# through the REAL normal-mode driver (real builtin_fcfs picker + a
+# stand-in allocator producing real PEND decisions via the same
+# make_pend_decision()/make_pendreason() production constructors) is
+# replayed through the REAL, unmodified simulation driver, and the two
+# resulting `.replay` files' ReplaySession.decisions lists are asserted to
+# match identically (same jobid, same pend reason content, per decision),
+# while never comparing ReplayHeader or SessionSummary fields (AC 7.1's own
+# "only non-decision metadata may differ" carve-out). First test file in
+# this directory to combine BOTH the normal-mode driver stack and the full
+# simulation stack in one TU -- see the test's own header comment for the
+# combined white-box #include set (test_record_lifecycle.c's own set union
+# test_sim_record_output.c's own set), the full stub surface, and why every
+# decision in this fixture is PEND rather than a DISPATCH/PEND mix
+# (sim_loop.c's sim_picker_thread_fn() can never emit a live DISPATCH today
+# -- a documented, out-of-this-task's-scope gap, not a weakening of this
+# test).
+sched_sim_equivalence_test = executable(
+    'sched_sim_equivalence_test',
+    ['test_sim_equivalence.c'],
+    include_directories:[incdir],
+    dependencies: [scheduler_test_deps],
+    install: false)
+
 # Register as meson tests so `meson test --suite scheduler` runs them all.
 # detect_leaks=0 matches the suite convention (fixtures are not torn down).
 test('scheduler test', scheduler_test, suite: 'scheduler',
@@ -697,3 +723,6 @@ test('scheduler sim alt events test',
 test('scheduler sim record output test',
      sched_sim_record_output_test, suite: 'scheduler',
      env: ['ASAN_OPTIONS=detect_leaks=0'])
+test('scheduler sim equivalence test',
+     sched_sim_equivalence_test, suite: 'scheduler',
+     env: ['ASAN_OPTIONS=detect_leaks=0'])