tools/chain.py: add --consumers to list what eats a material

Reverse of the existing make-vs-buy tree: given a ticker, find every
recipe that consumes it as an input, with each output's live market
depth. Answers "is there a deeper downstream product worth chaining
into" without an ad-hoc fio.recipes() scan each time (did this by hand
for BOR, BSE and BBH this session).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tools/chain.py

@@ -3,6 +3,7 @@
 Cost to make = inputs at min(buy, make) per output unit; wages/capex excluded unless --wages.
   tools/chain.py DEC                  # AI1
   tools/chain.py BHP --depth 3 --qty 13
+  tools/chain.py BOR --consumers      # what recipes EAT this ticker as an input, with the output's market depth
 """
 import argparse, sys
 from pathlib import Path
@@ -18,6 +19,7 @@ def main():
     ap.add_argument("--qty", type=float, default=1.0, help="units/day you would make (sourcing check)")
     ap.add_argument("--wages", action="store_true", help="add wage cost per output unit (both luxuries at ask)")
     ap.add_argument("--cogc")
+    ap.add_argument("--consumers", action="store_true", help="list recipes that consume this ticker as an input, with the output's market depth, instead of the make-vs-buy tree")
     a = ap.parse_args()
 
     snap = market.snapshot()
@@ -28,6 +30,24 @@ def main():
         for o in r["Outputs"]:
             by_out.setdefault(o["Ticker"], []).append(r)
 
+    if a.consumers:
+        tk = a.ticker.upper()
+        found = False
+        for r in fio.recipes():
+            if not any(i["Ticker"] == tk for i in r["Inputs"]):
+                continue
+            found = True
+            ins = " ".join(f"{i['Amount']}{i['Ticker']}" for i in r["Inputs"])
+            outs = " ".join(f"{o['Amount']}{o['Ticker']}" for o in r["Outputs"])
+            print(f"{r['BuildingTicker']:4} {ins} -> {outs}")
+            for o in r["Outputs"]:
+                q = Q(o["Ticker"])
+                mk = f"ask {q.ask:.0f} bid {q.bid:.0f} sup {q.supply:.0f} dem {q.demand:.0f} flow {sat.tref(q.traded7, q.traded30):.1f}/d" if q and q.ask and q.bid else "no market"
+                print(f"    {o['Ticker']:5} {mk}")
+        if not found:
+            print(f"nothing consumes {tk} as an input")
+        return
+
     def wage_per_day(b):
         tot = 0.0
         for t in econ.TIERS: