Close unit_place exactly: units.obj reaches 179/10/0

Census 178/11/0 -> 179/10/0 code, data unchanged at 129/0/0.

The residual was two coupled levers, which is why every previous attempt --
roughly 400 measured variants, including all 120 permutations of the local
declarations -- came out worse:

1. Split the unit.flags read-modify-write into a named temp, so the value is
   held in a register across the intervening frame_index store. On its own this
   is not enough; VC7 sinks it back past that store and re-folds it to
   or dword ptr [mem], imm.
2. The object.flags store must come AFTER the unit.flags store. With the object
   store first, VC7 re-folds the unit.flags update every time.

A sweep of all 210 legal orderings of the seven statements finds exactly seven
that are exact; the landed one is object-flags load, clamp, damage SET_FLAG,
unit-flags load-or, frame store, unit-flags store, object-flags store.

Two secondary facts: exactly one of the two dword read-modify-writes gets a
register temp unless both are forced, and forcing the other simply swaps which
one folds; and the eax/edx role swap seen in near misses is a size-driven
allocator preference (or eax,imm32 is five bytes against six for edx) that
resolves once the ordering is right.

Wave gates: /Zs exit 0 with no warnings; contained deletion with a dry run
proving exactly one CL edge; one emission; owner gate pinned to 8cdede3e shows
exactly one changed owner of 220, the intended one; determinism replay identical
across all 220 owners.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

source/units/units.c

@@ -4631,6 +4631,7 @@ void unit_place(
 		if (unit->unit.animation.state==_unit_state_dying)
 		{
 			unsigned long object_flags;
+			unsigned long unit_flags;
 			long death_frame_index;
 			struct animation_graph *animation_graph;
 			struct animation *animation;
@@ -4653,12 +4654,13 @@ void unit_place(
 				&animation_graph->animations,
 				unit->object.animation.state.index,
 				struct animation);
+			object_flags = unit->object.flags;
 			death_frame_index = MAX(0, animation->frame_count - 4);
 			SET_FLAG(unit->object.damage_flags, _object_dead_bit, TRUE);
-			SET_FLAG(unit->unit.flags, _unit_placed_here_dead_bit, TRUE);
-			object_flags = unit->object.flags;
-			unit->object.flags = object_flags | FLAG(_object_cannot_be_garbage_bit);
+			unit_flags = unit->unit.flags | FLAG(_unit_placed_here_dead_bit);
 			unit->object.animation.state.frame_index = (short)death_frame_index;
+			unit->unit.flags = unit_flags;
+			unit->object.flags = object_flags | FLAG(_object_cannot_be_garbage_bit);
 			unit->unit.time_of_death = game_time_get();
 			unit->object.body_vitality = 0.f;
 			unit->object.shield_vitality = 0.f;