Add CONTD contract evaluator, deadline-aware buy pricing, actpkg JSON generator

- puga/contd.py, tools/contd.py: price open CONTD contract offers against real
  buy-fresh cost, flagging conditions that can't be priced from the API alone.
- tools/buyat.py: cheapest bid price likely to fill by a hard deadline
  (stockout risk), using the empirical first-passage model from history.py.
- puga/actpkg.py, tools/actpkg.py: Refined PrUn XIT ACT buy-list JSON packages.

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

tools/contd.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python3
+"""List this account's OPEN CONTD contract offers (the NPC logistics-officer pool shown in APEX's
+CONTD panel - usually 3 at a time, only one acceptable) with payment, priced material requirements,
+and net. Judging the actual best deal is NOT this tool's job for anything it flags as unpriced
+(EXPLORATION, REPAIR_SHIP, etc. - see puga/contd.py's docstring) or for situational cheapness (a ship
+already flying that route, material already in free/uncommitted storage) - it reports the breakdown,
+the caller reasons about context.
+
+  puga contd
+  puga contd --cx AI1
+"""
+import argparse, sys
+from pathlib import Path
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+from puga import config, contd
+
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--cx", default=config.DEFAULT_CX)
+    a = ap.parse_args()
+
+    contracts = contd.open_contracts()
+    if not contracts:
+        print("no OPEN contract offers right now")
+        return
+
+    for c in contracts:
+        r = contd.evaluate(c, a.cx)
+        print(f"\n{r['id']}  partner={r['partner']}  deadline {r['deadline_days']:.1f}d"
+              + ("  +reputation" if r["reputation"] else ""))
+        print(f"  payment: {r['payment']:,.2f} AIC")
+        for req in r["requirements"]:
+            flag = "  SHORT: book can't fill this qty" if req["short"] else ""
+            print(f"  requires: {req['ticker']} x{req['qty']:g} @ {req['address']}  buy-fresh cost {req['cost']:,.0f}{flag}")
+        for ftype, addr in r["flags"]:
+            print(f"  UNPRICED CONDITION: {ftype}" + (f" @ {addr}" if addr else "") + "  - context-dependent, judge separately")
+        print(f"  material cost: {r['material_cost']:,.0f}  ->  net (payment - buy-fresh cost): {r['net']:,.0f}")
+
+    priceable = [c for c in contracts if not contd.evaluate(c, a.cx)["flags"]]
+    if len(priceable) == len(contracts):
+        best = max(contracts, key=lambda c: contd.evaluate(c, a.cx)["net"])
+        print(f"\nby buy-fresh net alone, best priced: {best['ContractLocalId']}"
+              " - but check storage for materials you may already hold before trusting this")
+
+
+if __name__ == "__main__":
+    main()