Ingot molds drop bars out of the bottom on their own

Bars no longer get thrown up into the furnace, and F is no longer needed to
collect them. Blocked bars wait in the trough; the short stub stays for the
next firing; F is optional upkeep (clean, chip slag, rake).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/PROJECT_MAP.md

@@ -199,7 +199,7 @@ Material ids, the material table (def), per-material property arrays, cell flags
 - functions: def, metalFamily
 - variables: EMPTY, GRASS, DIRT, LDIRT, SAND, GRAVEL, CLAY, STONE, GRANITE, BASALT, NMAT, MD, PH, DENS, KC, ICAP, CASTMETAL, METAL_TIER, SOLIDMETAL, F_NAT, F_CAST, F_BURN, P_NONE, P_TU, P_TD, P_TL, P_TR, P_GRATE, P_GOPEN, P_WHEEL, P_INTAKE, P_FILTER, P_PIPE, TDX, TDY, BIT_TIERS, TANK_TIERS, REACH
 
-### src/sim/pieces.js (140 lines)
+### src/sim/pieces.js (139 lines)
 Everything the player can build (PIECES): blocks, machines and molds, with costs and descriptions; filter settings; wall materials and their cost.
 - functions: isPipeCode, filterable, cleanFilterCfg, filterRec, filterPassAt, filterInfo, sameFilter, wallCost
 - variables: BS, BP_WALL, BP_BELT, BP_TUBE, BP_SHAFT, BP_GRATE, BP_GATE, BP_FILTER, BP_PIPE, BP_PUMP, BP_OUTLET, filterCfg, WALL_OF, WALL_LIST, BAR_OF, GRAINS_PER_BAR, POWER_FREE, CASH, PIECES, PIECE_BY_ID, PIECE_BY_CODE, BELT_POWER, TUBE_POWER, FAN_POWER, WHEEL_K, ENGINE_K, MOLDS
@@ -257,9 +257,9 @@ How belts, filters and screw tubes move what is on or in them. What rests on a b
 Building blocks: placing, integrity, removing, lines and rectangles of blocks.
 - functions: blockOf, blockCellList, pieceCost, canPlaceBlock, placeBlock, blockIntegrity, removeBlock, blockLine, blockRect, blockInReach, blockIs, placeBlocks
 
-### src/sim/molds.js (284 lines)
-Molds: cavities that fill with molten metal (or glass) and are knocked out as bars.
-- functions: moldCellsAt, canPlaceMold, newMoldRecord, addMold, castMix, cavityState, troughState, clearCavity, moldPlugCells, rakeAbove, furnaceJunkHint, unplugMold, checkMolds, moldAt, knockNote, tally, collectMold, removeMold
+### src/sim/molds.js (297 lines)
+Molds: cavities for castings; ingot troughs drop bars out of the bottom.
+- functions: moldCellsAt, canPlaceMold, newMoldRecord, addMold, castMix, cavityState, troughState, clearCavity, moldPlugCells, rakeAbove, furnaceJunkHint, unplugMold, ejectIngot, checkMolds, moldAt, knockNote, tally, collectMold, removeMold
 - variables: DROSS, grains
 
 ### src/sim/items.js (134 lines)
@@ -426,7 +426,7 @@ Previews drawn under the cursor: build ghosts, drill aim and pulses, selections,
 - functions: blockRectPx, drawGrid, previewColor, crackSeg, drawCracks, pulseRGB, fanPoints, drawDrillPulses, drawDrillAim, drawPreviews, drawTag, drawSelection, drawPastePreview
 - variables: CRACK_N, CRACK_LV, SEL_COL
 
-### src/ui/events.js (44 lines)
+### src/ui/events.js (50 lines)
 Events from the simulation (emit) turned into sounds, toasts and cards.
 - functions: drainEvents
 
@@ -447,7 +447,7 @@ The frame loop and boot.
 - `test/t_drill.js`: The resonance drill: pulses from the bot shake rock until it shatters. Widths trade area for speed, tuning shatters only one material and drains it out of the wall, built blocks are left alone, and the drill says why when nothing breaks.
 - `test/t_econ.js`: Economy: the dock (instant sale), orders, prices, the market dip, money for machines, alloys.
 - `test/t_furnace_repeat.js`: The starter furnaces keep working when fired again and again without cleaning, however the charge goes in: mixed, ore first with coal on top, or blown in through the vent. Each case plays furnace_play.js, which builds the design and fires it like a player.
-- `test/t_molds.js`: Molds and furnaces stay usable: knock-outs leave the mold clean, plugs over the mold are cleared, spoiled castings can be knocked out, grains never drop through a grate by teleporting, and slag lets the fire breathe.
+- `test/t_molds.js`: Molds and furnaces stay usable: ingots drop below and keep their stubs, plugs over molds are cleared, spoiled castings can be knocked out, grains never drop through a grate by teleporting, and slag lets the fire breathe.
 - `test/t_pipes.js`: Pipes, pumps and outlets move liquids; the Refiner grinds waste rock for trace ore.
 - `test/t_smooth.py`: The smooth look: the WebGL pass compiles, draws, falls back cleanly, and the thermal lens still works.
 - `test/t_stone.js`: Uses for waste rock and sand: glass bricks from a fan furnace, the stone cutter, the silo and builders' orders.