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>

puga/actpkg.py

@@ -0,0 +1,44 @@
+"""Refined PrUn (github.com/refined-prun/refined-prun) XIT ACT action-package JSON - the semi-auto
+buy-list format: importing one pre-fills the in-game CXPO buy tile for each material, the player
+still clicks the real buy button themselves. Schema confirmed from the extension's own source
+(src/store/user-data.types.d.ts, src/features/XIT/ACT/actions/cx-buy/cx-buy.ts, 2026-10-17).
+
+Gotcha (verified against the real extension, not just reading the source): `global.name` (and group/
+action names) get turned directly into an in-game command string by ActionPackageList.vue - spaces
+become underscores but other punctuation survives into the command literally, and APEX's command
+parser then rejects it with a generic "Illegal command" error on Edit/Execute (NOT on import, so it
+looks like the JSON is fine until you actually open it). sanitize_name() strips anything but
+letters/digits/spaces to avoid this.
+"""
+import re
+
+
+def sanitize_name(name: str) -> str:
+    return re.sub(r"[^A-Za-z0-9 ]", "", name).strip()
+
+
+def build_package(name: str, materials: dict[str, float], exchange: str = "AI1") -> dict:
+    """materials: {ticker: qty}. Quantities are rounded up to whole units (CXPO buy amounts aren't
+    fractional)."""
+    name = sanitize_name(name)
+    group = sanitize_name(name.lower()) or "group"
+    import math
+    mats = {tk.upper(): math.ceil(qty) for tk, qty in materials.items() if qty > 0}
+    return {
+        "global": {"name": name},
+        "groups": [
+            {"type": "Manual", "name": group, "materials": mats},
+        ],
+        "actions": [
+            {
+                "type": "CX Buy",
+                "name": f"Buy {name}",
+                "group": group,
+                "exchange": exchange,
+                "priceLimits": {},
+                "buyPartial": False,
+                "allowUnfilled": False,
+                "useCXInv": True,
+            }
+        ],
+    }