Ledger market gotcha: hoarding in place does not move the local price

In a simulation where a market price is computed from supply-at-a-location, and supply-at-a-location = the location stock PLUS the stock of every entity located there, a merchant that buys and HOARDS in place does NOT reduce local supply (its hoard is still counted at that location) — so the present price does not move. To model reflexivity (buying ahead pushing the present price up toward a forecast) the buyer must pull goods OFF that market: be located elsewhere and ship it out, or consume it. This bit an experiment where buying 40 units left the price unchanged (9.02 -> 9.02) until the buyer was moved to a different settlement (then 9 -> 26). Second discovery: when generalizing a spatial reservation/value-iteration field to a multi-commodity graph (nodes = location x resource, edges = spatial move + market swap + production recipe), a value-creating production recipe (product worth more than inputs) makes ordinary value iteration DIVERGE — and that divergence IS the money-pump / arbitrage-cycle signal (equivalently a Bellman-Ford negative cycle on -log(rate)); cap the iterations and treat did-not-settle as detected arbitrage.