feat: shop system removed from talk system, added per-item restock and variable pricing

1 files changed, 5 insertions, 1 deletions

diff --git a/AGENTS.md b/AGENTS.md
index f7061a2..42e08e9 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -90,9 +90,13 @@ Used by exits, talk options, on-enter, use_interactions: `flag` (world), `player
 
 `DropDespawnTicks = 1000`. `ReserveTicks = 100` (mob loot reserved for killer). Same-ID items NOT merged. Spawn items respawn with merge. Despawn/reserve visible via options.
 
+## Drop Resolution (`behavior/store.go`)
+
+Drop tables are skill-independent weighted lists of items. `ResolveDrop` does one weighted pick; if the picked entry is a `table:` ref, its `quantity` yields that many copies of a single sub-roll (used by gather/search/steal). `ResolveDropList` (mob loot only, `combat_mob.go`) instead treats a picked table entry's `quantity` as the number of **independent rolls** against the sub-table (each may differ), returning one entry per roll; a plain item entry yields one result. Mob loot is still a single weighted pick per kill — a table entry just expands into N sub-rolls.
+
 ## Shop System (`cmd_shop.go`)
 
-Root-level `shop:` on a MobDef (`behavior.ShopConfig`) — NOT part of the talk tree. Traded via plain `StateGame` commands: `list`, `buy <item>`, `sell <item>`, with `list <mob>` / `buy <item> from <mob>` / `sell <item> to <mob>` to disambiguate when a room has multiple shop mobs (else "Which shop?"). No bespoke shop CLI/session state. **Prices derive from item `value:`** — shops sell at 100% of value; buy back via OSRS formula `value×max(10, buy_percentage−stock×change_percentage)/100` (defaults `buy_percentage: 40`, `change_percentage: 3`, floor 10%). Per-item `stock` (target+starting); buying depletes (out of stock at 0), selling raises it (lowering next sell price). Restock moves current stock toward target one step per `restock_ticks` (item override → shop default → `ShopDefaultRestock=100`) in **both** directions; dynamic (unlisted) items decay to 0. `buys_anything` (default true) lets specialty shops refuse unlisted items. **Live stock is per-MobInstance, in-memory only** (`ShopStock`/`ShopRestock` maps), mutated only under `MobStore.mu` via `ShopTake`/`ShopAdd`/`ShopStockOf`; restock runs in `MobStore.Tick()`.
+Root-level `shop:` on a MobDef (`behavior.ShopConfig`) — NOT part of the talk tree. Traded via plain `StateGame` commands: `list`, `buy <item>`, `sell <item>`, with `list <mob>` / `buy <item> from <mob>` / `sell <item> to <mob>` to disambiguate when a room has multiple shop mobs (else "Which shop?"). No bespoke shop CLI/session state. **Prices derive from item `value:`** — shops sell at 100% of value; buy back via OSRS formula `value×max(10, buy_percentage−stock×change_percentage)/100` (defaults `buy_percentage: 40`, `change_percentage: 3`, floor 10%). Per-item `stock` (target+starting); buying depletes (out of stock at 0), selling raises it (lowering next sell price). Restock moves current stock toward target one step per item `restock_ticks` (default `behavior.ShopDefaultRestock`, set from `game_constants.shop_default_restock` in config.yaml = 1000) in **both** directions; dynamic (unlisted) items decay to 0. `buys_anything` (default true) lets specialty shops refuse unlisted items. **Live stock is per-MobInstance, in-memory only** (`ShopStock`/`ShopRestock` maps), mutated only under `MobStore.mu` via `ShopTake`/`ShopAdd`/`ShopStockOf`; restock runs in `MobStore.Tick()`.
 
 ## Combat System