re: built-in 12 is activate_unit — 517/517 on the ordering test

The highest-traffic unnamed built-in: 1197 sites across all 28 stages.
sub_822659F0 read directly:

* indexes [phase+324]'s record array by the slot-4 symbol;
* returns 0 immediately when the live object [record+4] is NULL, so it
  registers an object that already exists rather than spawning one;
* sets [record+16] = 2, the documented "active" state every unit predicate
  tests;
* stores sub_82301118's packed result into [record+20] (low 16) and
  [record+24] (high 16) -- member counts;
* posts opcode 513 (0xAB0201BA) either way; the slot-8 mode (1 in 999 sites,
  0 in 198) only decides whether cmd+20 is also set to 1.

The ordering test: if this activates a unit for the script, no predicate
should test a unit before it. Over all 28 stages, for every (stage, unit)
pair having both, activate_unit comes first 517 times and a predicate first
0 times. Recorded as file order rather than proven execution order --
coroutines can interleave -- but 517 with no exceptions is not a coincidence.
344 units are tested without ever being activated (live from mission start)
and 203 activated without being tested.

Also recorded: a tidy closure that FAILS. squad_survival_pct reports current
over initial and activate_unit snapshots counts, so the snapshot looks like
the baseline. It is not -- built-in 24 reads [record+16] for the state then
calls sub_823011B0 and sub_82301118 on the LIVE object, never touching
+20/+24. What reads those two fields is unidentified.

Named coverage is now 57 of 108 distinct ids and ~80% of call-site traffic.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PMRJjbxLqZtsb5Vb7KunPE

docs/re/data/isl-stage02.txt

@@ -93,6 +93,7 @@ Generated by `tools/re-capture/isl_report.py calls`.
   47  squadron_attack           137
   15  set_group_speed           127
   18  dist_lt                    92
+  12  activate_unit              86
   5   kill_coroutine             83
   70  unit_alive                 71
   56  unit_relation              52