bugfix(saveload): Save the next evaluation frame of delayed scripts

[bobtista]

• Fixes Scripts with a delayed evaluation run immediately after loading a save #3129

Script::xfer only transfers the active flag, so m_frameToEvaluateAt is never restored when a save is loaded. ScriptList::xfer walks the scripts that were rebuilt from the map rather than creating them from the save, so nothing else restores it either, and the field keeps whatever checkConditionsForTeamNames assigned during setup - a random stagger of 0 to 60 frames. Any real load frame is past that, so ScriptEngine::executeScript's frame check always passes: every script with a delay evaluates on its first pass after loading and then re-times itself from the load frame, losing both the remainder of its interval and its original stagger. 893 scripts across 35 stock maps use a non-zero delay, including every Generals Challenge map and most campaign missions.

Now the field is transferred in a version 2 xfer, so a delayed script resumes on the frame it was already waiting for. Version 1 saves still load and keep the old behaviour. The field also moves above the "Runtime fields - not saved or read" comment in the header, since it is now saved.

Measured on MD_CHI01 by saving at logic frame 3000 and loading the save back, logging the field on both sides of the xfer. The numbers are m_frameToEvaluateAt itself, an absolute logic frame at 30 frames per second:

script	evaluation delay	next eval frame, saved	after load, before	after load, after
Attack Wave 3 Condition	20s	14	49	14
Attack Wave 2 Condition	30s	48	23	48
Attack Wave 1 Condition	40s	24	8	24
Attack Wave 1 Condition - EASY	40s	4	52	4

Before the fix the load replaces the saved value with a freshly generated stagger, after the fix it round-trips exactly.

Todo:

• Verify on MD_CHI01: save at frame 3000, load, confirm each delayed script's next evaluation frame is restored
• Replicate to Generals