Prototype CHOAM Nexus Collection trade and inventory Discoveries

An unallied player holding CHOAM Nexus while CHOAM is absent can now discard one Worthless card during Spice Collection for two bank spice. The server spends both physical cards once, exposes only private legal card choices, and persists an already-paid discard receipt. Human controls and all four AI profiles share the action. The after-victory inspection alternative remains missing; normal unfinished modes and publication stay gated.

Independent review caught and fixed a queued Grumman Collection lock mismatch. Focused tests cover Basic/Advanced, actual card custody, private controls, all AI profiles, stale and wrong-mode rejection, Truthtrance and Grumman locks, JSON corruption/replay, competing production SQLite writes and private seat restoration.

A separate bounded acquisition helper recorded all seven Discovery Spice Cards, eight tokens and exact physical card placements from publisher-authored sources. Discovery runtime remains missing.

Validation: types, lint, 4,217 offline tests, production build and 40 HTTP tests passed. Durations: check 139298 ms; build 6617 ms; HTTP 24329 ms. Source fingerprint dfdaaf8bafe69acd31c9d0afc13f7a0d070da43deb544f091e95fe840b399493; private report under ~/.local/share/dune/checkpoints/20260913-choam-nexus-trade/verification/report.json. Browser reference search, Prototyped label and related Collection link checked. All 95 opening saved rooms unchanged; 30 HTTP test rooms added, 125 total. No server restart or database reset.

Efficiency counter: 59,982,405 at batch start; 60,581,959 after broad verification, delta 599,554 aggregate tokens before final preservation/Git/usage checks. One newly playable function plus the acquired Discovery inventory; this is not full CHOAM or Nexus compliance.

docs/IMPLEMENTATION_STATUS.md

@@ -1,5 +1,22 @@
 # Dune implementation status
 
+## 13 September 2026 — CHOAM Nexus Collection prototype and Discovery inventory
+
+Adds the missing absent-CHOAM Secret Ally Collection trade through the engine,
+private physical-card selector/inspector, all four AI profiles and JSON discard
+continuation. Both cards are spent for exactly two bank spice; stale actions,
+competing SQL writes and saved replay cannot duplicate the payment. The separate
+battle inspection remains missing. See [contract and scope](NEXUS_CHOAM_SECRET_ALLY.md).
+Independent review found a queued Grumman Collection lock mismatch; the server
+and private offer now share that automatic-continuation block.
+
+A bounded acquisition helper resolved [all Discovery component identities and
+card placements](DISCOVERY_COMPONENTS.md). No Discovery runtime is claimed.
+Focused trade tests pass; checkpoint-wide check/build/HTTP results are recorded
+in the verified commit and private source-bound report. Existing mode and
+publication gates remain closed. No server restart or saved-game reset is needed.
+
+
 ## 13 September 2026 — Genuine Ix expansion prototype
 
 Connected Basic/Advanced Ix setup with both expansion factions, the complete