Split FX out of the park plan: flag-only plans, derived online-first FX work list, two-half record release, applied-state fingerprint

tests/test_view_fx_park.cpp

@@ -45,14 +45,14 @@ struct FlagValues {
 static void testAChainSittingAtEveryValueTheParkWouldWriteReadsAsParked() {
     // The four zeros are what a parked track's driven flags actually read; if
     // makeParkPlan ever writes something else, this is the test that says so.
-    const TrackPlan park = makeParkPlan("{A}", /*fxCount=*/0);
+    const TrackPlan park = makeParkPlan("{A}");
 
     CHECK(park.flags.size() == 4);
     CHECK(parkFlagsAlreadyApplied(park.flags, FlagValues{0, 0, 0, 0}));
 }
 
 static void testOneFlagStillAtTheUsersValueMeansNoParkReachedTheChain() {
-    const TrackPlan park = makeParkPlan("{A}", /*fxCount=*/0);
+    const TrackPlan park = makeParkPlan("{A}");
 
     // Each case varies exactly one flag, so together they also prove all four are
     // in the plan: a missing op makes its case read parked and fail here.