Phase 7: PlayerVendorSale core event + subscriber

The one non-drop-in piece. Player-vendor purchases raise no EventSink, so the
sale is invisible to subscription. Two git-format core patches add a
PlayerVendorSale event and raise it at the committed sale in
PlayerVendorBuyGump.OnResponse (right after HoldGold +=), where buyer, vendor
owner, item, price, and commission are all in scope. The subscriber
BridgeVendorSale emits vendor.sale.

All three are a coupled unit. The subscriber references PlayerVendorSaleEventArgs,
which does not exist until the EventSink patch is applied, so it lives in patches/
not overlay/ -- shipping it in overlay would break the build on any unpatched
install. patches/README.md documents applying the unit; both patches verified
with git apply --check against stock ServUO 57.4. This is the first phase that
rebuilds the core (ServUO.exe), not just Scripts.dll.

vendor.sale carries buyer and vendor-owner accounts, both present and distinct,
which is the pair that flags gold-laundering when they match -- richer than the
ownerless NPC ValidVendor* events, and on a committed sale rather than a
validation stage.

Verified with a probe firing the event on real seeded-vendor data: vendor.sale
emitted with buyerAcct=seed_001, ownerAcct=seed_000, Longsword, price 69819. The
probe proves the event, args, subscriber, and payload; the literal gump call site
firing on a real purchase needs a live buyer with a NetState and is confirmed by
an in-game buy. Evidence in docs/PLAN.md §17.

This completes every phase on the ServUO side. Phases 0-6 are drop-in (overlay/);
7 is patches/. Cheat signals are folded into existing streams (fastwalk, audit,
vendor.sale), not a separate phase. Remaining work is the Rust sidecar.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/scaffolding/BridgeVendorSaleProbe.cs

@@ -0,0 +1,104 @@
+using System;
+
+using Server.Accounting;
+using Server.Items;
+using Server.Mobiles;
+
+namespace Server.Custom
+{
+    /// <summary>
+    ///     Fires PlayerVendorSale with real seeded-vendor data to prove the full chain: the
+    ///     EventSink event added by the Phase 7 patch, its args, the subscriber, and the vendor.sale
+    ///     JSON. It does NOT exercise the gump call site (that needs a live buyer with a NetState) —
+    ///     the hook line is placed at the committed-sale point in PlayerVendorBuyGump.OnResponse and
+    ///     is verified by a real in-game purchase.
+    ///
+    ///     Test scaffolding. Never deployed. Read-only (invokes an event; changes no world state).
+    /// </summary>
+    public static class BridgeVendorSaleProbe
+    {
+        public static void Initialize()
+        {
+            if (Config.Get("Bridge.VendorSaleProbeOnStart", false))
+                EventSink.ServerStarted += () => Timer.DelayCall(TimeSpan.FromSeconds(4.0), Run);
+        }
+
+        private static void Run()
+        {
+            try
+            {
+                var vendors = PlayerVendor.PlayerVendors;
+
+                if (vendors == null || vendors.Count == 0)
+                {
+                    Console.WriteLine("[VendorSaleProbe] no player vendors; seed the world first");
+                    return;
+                }
+
+                // A real seeded vendor, its owner, and one of its actual priced items.
+                PlayerVendor vendor = null;
+                Item item = null;
+                int price = 0;
+
+                foreach (var v in vendors)
+                {
+                    if (v == null || v.Deleted || v.Owner == null || v.Backpack == null)
+                        continue;
+
+                    foreach (var it in v.Backpack.Items)
+                    {
+                        var vi = v.GetVendorItem(it);
+                        if (vi != null)
+                        {
+                            vendor = v; item = it; price = vi.Price;
+                            break;
+                        }
+                    }
+
+                    if (vendor != null)
+                        break;
+                }
+
+                if (vendor == null)
+                {
+                    Console.WriteLine("[VendorSaleProbe] no vendor with a priced item found");
+                    return;
+                }
+
+                // A buyer on a DIFFERENT account than the owner, so buyerAcct != ownerAcct.
+                Mobile buyer = null;
+                foreach (Account a in Accounting.Accounts.GetAccounts())
+                {
+                    if (!a.Username.StartsWith("seed_", StringComparison.Ordinal))
+                        continue;
+
+                    var pm = a[0] as PlayerMobile;
+                    if (pm != null && pm != vendor.Owner &&
+                        !(vendor.Owner != null && vendor.Owner.Account == a))
+                    {
+                        buyer = pm;
+                        break;
+                    }
+                }
+
+                int commission = 0;
+                if (vendor.IsCommission)
+                    commission = (int)(price * (vendor.CommissionPerc / 100));
+
+                Console.WriteLine("[VendorSaleProbe] firing PlayerVendorSale: buyer={0} owner={1} item={2} price={3} commission={4}",
+                    buyer == null ? "?" : buyer.Name,
+                    vendor.Owner == null ? "?" : vendor.Owner.Name,
+                    item.GetType().Name, price, commission);
+
+                EventSink.InvokePlayerVendorSale(
+                    new PlayerVendorSaleEventArgs(buyer, vendor, vendor.Owner, item, price, commission));
+
+                Console.WriteLine("[VendorSaleProbe] done; watch for vendor.sale");
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine("[VendorSaleProbe] FAILED: " + ex);
+            }
+        }
+    }
+}

tools/scaffolding/README.md

@@ -12,6 +12,7 @@ These two scripts produced the measured budget in `docs/PLAN.md` §1. They are k
 | `BridgeSweepProbe.cs` | `Scripts/Custom/BridgeSweepProbe.cs` | Bumps one seeded house's decay stage after baseline so the decay sweep's transition detection can be observed without waiting a real IDOC stage. Flag: `SweepProbeOnStart`. Pair with short `*SweepSeconds` overrides. |
 | `BridgeLinkProbe.cs` | `Scripts/Custom/BridgeLinkProbe.cs` | Triggers `[link` for seed_001 without a client, then saves so the `WebsiteUserId` tag reaches `accounts.xml`. Flag: `LinkProbeOnStart`. Pair with a sidecar that reads the code and sends `link.confirm`. |
 | `BridgeCrierProbe.cs` | `Scripts/Custom/BridgeCrierProbe.cs` | Logs the global town-crier entry list every 3s so `towncrier.add` / `remove` can be seen landing in game state. Flag: `CrierProbeOnStart`. |
+| `BridgeVendorSaleProbe.cs` | `Scripts/Custom/BridgeVendorSaleProbe.cs` | Fires `PlayerVendorSale` (Phase 7) with real seeded-vendor data so `vendor.sale` can be verified without a live buy. Requires the Phase 7 patches applied. Flag: `VendorSaleProbeOnStart`. |
 
 ## Deploy overwrites Bridge.cfg