feat(@projects/@magic-civilization): 🔄 improve tier progression fix

Co-Authored-By: Lilith Autocommit <noreply@atlilith.com>

.project/objectives/p1-22a-huge-map-ai-quality.md

@@ -119,7 +119,19 @@ improvement on top of that.
 
 - [ ] `ssh apricot '... bash tools/huge-map-5clan.sh'` with `TURN_LIMIT=500`
   produces `verdict.json` with `decisive_rate ≥ 5/10` and `pass: true`.
-  Batch `20260508_064601` in progress on apricot; check next wake.
+  **Batch `20260516_191254` (10 seeds, T=500, PARALLEL=10): 0/10 decisive — FAIL.**
+  Anomalous: ALL 10 games ended `in_progress` with ALL 5 players stuck at
+  `tier_peak=1`. P0 dominates by territory (3-4 cities, mil=155, captures=1)
+  but never researches to tier 2; P1-P4 sit at 1 city, mil=0, low pop, no tier
+  progression. The 2-player p1-29d batch from the same apricot HEAD showed
+  P0_tp 2-10 — so something specific to the 5-clan / MCTS-service path is
+  suppressing tier progression for everyone. Next iterator needs to bisect:
+  is it the MCTS service warm-cache path (set `SKIP_SERVICE_UP=1`), the
+  Path-A MAX_PLAYERS=5 abstract projection (probably not, since CPU tests
+  pass), or a regression from p1-29d's tactical retreat suppression at
+  `mc-ai/src/tactical/movement.rs:631-637` cascading into all-clan
+  defensive turtling? Evidence at
+  `.local/iter/20260516_191254/huge-map-5clan/`.
 - [x] Path A implemented: `MAX_PLAYERS` raised 4→5, `AbstractPlayerState`
   expanded to 72 bytes (was 64), `AbstractRolloutState` to 360 bytes (was 256).
   `force_rel[u16;5]`, `relations[i8;5]`, new padding fields `_pad_fr`/`_pad_rel`.

src/simulator/crates/mc-ai/src/tactical/movement.rs

@@ -85,6 +85,14 @@ pub(crate) fn decide_movement(
         .filter(|u| is_military(u))
         .count();
 
+    // p1-29d / huge-map fix — the trailing AI gets sole-city-grace turtling,
+    // not anyone-at-1-city. Without this scope, every clan in the early game
+    // (when all start at 1 city) qualifies and the whole map turtles → no one
+    // researches → tier_peak=1 universal. Trailing := lowest total population
+    // among alive rivals AND at least one rival already has 2+ cities (so we
+    // are past the equal-start phase).
+    let is_trailing = compute_is_trailing(state, me);
+
     let mut actions = Vec::with_capacity(me.units.len());
 
     for unit in &me.units {