feat(@projects/@magic-civilization): ✨ add claudes unit/explosion and building completion fixes

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

.project/objectives/p2-67-claude-player-api.md

@@ -1322,3 +1322,122 @@ attack actions and 951 fortify actions. Two compounding bugs:
   `UnitKilled`, so net wire behaviour is correct. AI memory /
   chronicle subscribers that consume `CivilianDestroyed` separately
   are unaffected.
+
+## 2026-05-12 — Real-game analysis follow-up: Bug 2 (unit explosion) + Bug 4 (buildings never complete)
+
+Both bugs touch `mc-turn::processor.rs` and were fixed in one pass.
+
+### Bug 2 — Unit explosion (1696 AI units in 250 turns)
+
+**RC**:
+- `try_spawn_unit` at `mc-turn/src/processor.rs:1179-1301` hardcoded
+  `unit_upkeep.push(0)` for every spawn — every unit cost zero gold to
+  maintain, so the gold economy had no brake on unit growth.
+- No gold gate and no unit cap; the only filter was `production_stored
+  >= cost (8)`, with production carrying over even after a spawn.
+- The insolvency handler at lines 709-718 disbanded only ONE unit per
+  turn even when net_gold was hugely negative — a deficit much larger
+  than one unit's upkeep could never claw back to solvency.
+
+**Fix**:
+- New module constants: `DEFAULT_UNIT_UPKEEP: i32 = 1` and
+  `SPAWN_GOLD_FLOOR: i32 = -100` at the top of `processor.rs`.
+- Every `unit_upkeep.push(...)` in `try_spawn_unit` and
+  `spawn_unit_typed` now pushes `DEFAULT_UNIT_UPKEEP` instead of `0`.
+- New gold-viability gate in `try_spawn_unit`: before any spawn this
+  turn, compute `projected = player.gold - (units+1)*DEFAULT_UNIT_UPKEEP`.
+  If `projected < SPAWN_GOLD_FLOOR`, skip ALL spawn candidates this
+  turn — production stays accumulated for next turn.
+- Insolvency cascade in `process_player_economy` now disbands units in
+  a `while player.gold < 0 && !player.units.is_empty()` loop, each
+  disband refunding `DEFAULT_UNIT_UPKEEP` to the running balance. Gold
+  is clamped to 0 if the cascade ends while still in debt.
+
+**Idle-suppression DEFERRED**. The bench harness has no AI policy that
+queues units for AI slots — the existing "AI builds ≥ 1 unit by turn
+10" hard constraint in `full_game_transcript` depends on the
+empty-queue auto-warrior fallback path. Removing that fallback would
+fail the test for a real reason (no mechanism queues for AI slots).
+The legacy empty-queue auto-warrior is preserved as documented
+tech debt; the gold gate alone brought slot-1 unit count from
+**1696 → 418** (~4× reduction) and Claude's score-leading slot now
+reaches 9580 gold instead of 0 (no upkeep load).
+
+### Bug 4 — Buildings never complete
+
+**RC**:
+- `process_city_production` at `mc-turn/src/processor.rs:954-1124` had a
+  `Queueable::Wonder` completion branch but NO branch for
+  `Queueable::Item` (buildings) — items queued via
+  `apply_queue_production` accumulated production forever.
+- `try_spawn_unit` ignored the queue entirely and hardcoded
+  `dwarf_warrior` regardless of what was queued. An item-queued city
+  silently became a warrior factory once its production caught up with
+  `unit_spawn_cost (8)`.
+- No `CityBuildingCompleted` variant existed in `mc-replay::TurnEvent`
+  (only `WonderBuilt` and `UnitCreated`).
+
+**Fix**:
+- New `TurnEvent::CityBuildingCompleted { turn, clan, city, building_id,
+  hex }` variant in `mc-replay/src/event.rs`. Pattern-listed in the
+  `turn()` accessor.
+- New `Queueable::Item` completion branch in
+  `process_city_production` parallel to the wonder branch: when
+  `production_stored >= queue_cost`, clear the queue, fold the building
+  id into `player.city_buildings[ci]`, and push the
+  `CityBuildingCompleted` event.
+- `try_spawn_unit` now respects the queue:
+  - `queue: None` → legacy `dwarf_warrior` auto-fallback (preserved
+    for bench AI's "≥ 1 unit by turn 10" constraint).
+  - `queue: Some(Queueable::Unit { unit_id })` → spawn the SPECIFIC
+    unit_id, then clear the queue.
+  - `queue: Some(Queueable::Item { .. } | Queueable::Wonder { .. })` →
+    skip — those are completed in `process_city_production`.
+- `mc-player-api::dispatch::translate_processor_events` gained a new
+  arm for `CityBuildingCompleted` that surfaces
+  `Event::CityBuildingCompleted` on the wire.
+
+### Regression tests (mc-turn/src/processor.rs `mod tests`)
+
+- `p2_67_bug4_item_queue_completes_and_emits_event` — queues a
+  `Queueable::Item { "library" }` with cost 30, production_stored 30;
+  steps `process_city_production`; asserts queue cleared,
+  `city_buildings` contains "library", `CityBuildingCompleted` event
+  fired.
+- `p2_67_bug4_unit_queue_respects_specific_unit_id` — queues a
+  `Queueable::Unit { "pikeman" }`; calls `try_spawn_unit`; asserts the
+  spawned unit's `unit_id` is "pikeman" (not hardcoded
+  `dwarf_warrior`) and the queue is cleared.
+- `p2_67_bug2_gold_gate_blocks_spawn_when_insolvent` — player at
+  `SPAWN_GOLD_FLOOR` with 200 units, calls `try_spawn_unit`; asserts no
+  new unit spawned and `production_stored` was NOT spent.
+- Updated `t7_process_economy_insolvency_disbands_one_unit_per_turn`
+  to match the new cascade contract (3 units, -52 gold → cascade
+  disbands all three in one turn).
+
+### Long-game evidence (250-turn `long_game_transcript`)
+
+Before fix: `Buildings completed = 0`, slot-1 unit count = 1696.
+
+After fix:
+- `Buildings completed (CityBuildingCompleted): 216` (matches 216
+  `queue_building` actions dispatched by Claude — 1:1).
+- Slot-1 unit count = **418** (4× reduction from 1696). Slot-1 still
+  has 52 cities pumping units, so the absolute count remains high; the
+  gold gate gates correctly but doesn't impose a hard cap.
+- Claude (slot 0) reaches gold = 9580, cities = 0 at end (lost cities
+  to slot 1's military, but no longer hemorrhaging gold to nonexistent
+  unit upkeep).
+- Action signature table shows `queue_building: 216` firing, matching
+  the new completion-event count.
+
+Artifact: `.local/demo-runs/2026-05-12-claude-vs-easy-ai-250-turn/recap.md`.
+
+### Pre-existing failures unaffected by this fix
+
+- `tests/full_turn_golden.rs::twenty_turn_golden_state` was already
+  asymmetric (`p0.gold = 306`, `p1.gold = 320`) before any p2-67 work;
+  confirmed by `git stash` baseline run. Pre-existing.
+- `mc-ai/tests/gpu_walltime.rs` and related GPU-pipeline tests have
+  pre-existing compile errors from a `TacticalState`/`AbstractPlayerState`
+  field rename. Pre-existing.