fix(@projects/@magic-civilization): 🐛 debug ai research tiering bugs

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

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

@@ -151,6 +151,31 @@ improvement on top of that.
   in `policy.rs` — when 4 of 5 players are below median, it may be
   over-firing and skewing every clan toward defensive Defend/Settle
   priorities at the expense of Research.
+
+  **2026-05-16 cycle 3**: ROOT-CAUSED. The "tier_peak=1 universal" was three
+  bridge-layer JSON-schema bugs in sequence:
+  1. `pick_research` (api-gdext/src/ai.rs:711) — strict `i32` parse of
+     personality_axes failed on Godot's `JSON.stringify` float emission
+     (`6` → `6.0`). FIX: `parse_godot_axes_json_flex` free helper accepts
+     both forms; 4 regression tests added. Commit `130552256`.
+  2. `pick_culture_tradition` (api-gdext/src/ai.rs:649) — identical
+     strict-parse bug. Commit `a7b8f3e7d`.
+  3. `_process_research` in `turn_processor.gd:142` early-returned when
+     `player.researching` was empty. Auto_play.gd only sets that field on
+     the player slot it impersonates (P0), so AI players P1..P4 stayed at
+     `techs=1` indefinitely. FIX: new `_auto_pick_research` helper called
+     in-line; mirrors candidate construction from auto_play.gd. Commit
+     `5b672e500`.
+
+  Result on batch `20260516_215115` (10 seeds, T=500): median
+  `winner_tier_peak = 9` (was 1 — gate ≥4 PASS), median `tier_peak_gap = 5`
+  (gate ≤4 close miss by 1), per-game tech counts P0=45 P1=30 P2=35 P3=30
+  P4=14 in seed1 (vs 1/1/1/1/1 prior). All 5 personality clans now
+  progress through eras independently. `decisive_rate ≥ 5/10` still 0/10
+  (games stop at wall-clock ~960s with `outcome=in_progress` — separate
+  infra signal cuts games off before natural victory; systemd unit
+  `Result=success` so it isn't a unit-level timeout). That's the
+  remaining work for next iterator.
 - [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`.