fix(critical): remove dead manifold.get_probability() from legacy scan and fix BUY_NO payout calculation

- Legacy scan called ManifoldClient.get_probability(), removed in the v3
  matcher migration, causing AttributeError when positions had changed
  family keys. The block used Manifold to escalate positions to
  CLOSE_RECOMMENDED (inversion detection) — a trading decision forbidden
  under MANIFOLD_SIGNAL_ENABLED=false — so the dependency is removed
  entirely; the scan keeps family re-keying and sibling-conflict logic.

- PaperExecutor.close_position() computed cash += position_cost * resolution,
  ignoring direction: a winning BUY_NO (resolution=0.0) paid out $0 and
  reported a loss. Now settles per trade:
    BUY_YES: payout = shares * resolution
    BUY_NO:  payout = shares * (1 - resolution)
  with pnl = payout - net_cost; Telegram win/loss keys off pnl > 0.
  Adds read-only Database.get_open_trades_for_market().

- tests/test_paper_close.py covers the 4 deterministic payout cases;
  tests/conftest.py shims datetime.UTC for local Python 3.10 (prod is 3.11).

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

bot/main.py

@@ -223,14 +223,17 @@ async def run_trading_loop(
 async def run_legacy_scan(
     db: Database,
     markets: list,
-    manifold: ManifoldClient,
     executor: PaperExecutor,
     paper_mode: bool,
 ) -> None:
     """
     One-time startup scan: re-key all open DB positions with the current
-    market_family_key() logic, detect contradictions, re-validate Manifold
-    signals, and report KEEP / REVIEW / CLOSE_RECOMMENDED per position.
+    market_family_key() logic, detect family conflicts, and report
+    KEEP / REVIEW / CLOSE_RECOMMENDED per position.
+
+    Manifold is intentionally not consulted here: with
+    MANIFOLD_SIGNAL_ENABLED=false it is observational-only and must not
+    drive position closures.
 
     In paper_mode: auto-closes all CLOSE_RECOMMENDED positions after logging.
     """
@@ -269,8 +272,6 @@ async def run_legacy_scan(
             "family_key_old": old_fk,
             "family_key_new": new_fk,
             "fk_changed": new_fk != old_fk,
-            "manifold_prob_new": None,
-            "manifold_inverted": False,
             "recommendation": "legacy_incomplete" if is_legacy_incomplete else "OK",
             "rec_reason": "edge_net and live market unavailable" if is_legacy_incomplete else "no family conflict",
         })
@@ -308,31 +309,7 @@ async def run_legacy_scan(
                 p["market_id"], p["family_key_old"] or "none", p["family_key_new"],
             )
 
-    # Step 3: Manifold re-query for positions whose family key changed
-    for p in enriched:
-        if p["live_market"] and p["fk_changed"]:
-            prob = await manifold.get_probability(p["question"])
-            p["manifold_prob_new"] = prob
-            if prob is not None:
-                # Detect if original trade direction conflicts with corrected Manifold signal
-                if prob < 0.40 and p["direction"] == "BUY_YES":
-                    p["manifold_inverted"] = True
-                    note = f"Manifold:{prob:.3f} contradicts BUY_YES (inversion bug confirmed)"
-                    if p["recommendation"] in ("OK", "REVIEW"):
-                        p["recommendation"] = "CLOSE_RECOMMENDED"
-                        p["rec_reason"] = note
-                    else:
-                        p["rec_reason"] += f" | {note}"
-                elif prob > 0.60 and p["direction"] == "BUY_NO":
-                    p["manifold_inverted"] = True
-                    note = f"Manifold:{prob:.3f} contradicts BUY_NO (inversion bug confirmed)"
-                    if p["recommendation"] in ("OK", "REVIEW"):
-                        p["recommendation"] = "CLOSE_RECOMMENDED"
-                        p["rec_reason"] = note
-                    else:
-                        p["rec_reason"] += f" | {note}"
-
-    # Step 4: log the full scan report (before any closures)
+    # Step 3: log the full scan report (before any closures)
     n_close    = sum(1 for p in enriched if p["recommendation"] == "CLOSE_RECOMMENDED")
     n_keep     = sum(1 for p in enriched if p["recommendation"] == "KEEP")
     n_ok       = sum(1 for p in enriched if p["recommendation"] == "OK")
@@ -348,7 +325,6 @@ async def run_legacy_scan(
             "  [%-18s] market=%-8s | dir=%-8s | edge_net=%+.3f\n"
             "                        stored_family: %s\n"
             "                        new_family:    %s%s\n"
-            "                        manifold_new:  %s\n"
             "                        reason: %s",
             p["recommendation"],
             p["market_id"], p["direction"],
@@ -356,12 +332,11 @@ async def run_legacy_scan(
             p["family_key_old"] or "none",
             p["family_key_new"],
             " [CHANGED]" if p["fk_changed"] else "",
-            f"{p['manifold_prob_new']:.3f}" if p["manifold_prob_new"] is not None else "n/a",
             p["rec_reason"],
         )
     log.warning("━" * 70)
 
-    # Step 5: auto-close in paper mode
+    # Step 4: auto-close in paper mode
     if paper_mode and n_close > 0 and isinstance(executor, PaperExecutor):
         log.warning("PAPER MODE: auto-closing %d CLOSE_RECOMMENDED position(s)...", n_close)
         for p in enriched:
@@ -414,7 +389,7 @@ async def main() -> None:
     except Exception as e:
         log.warning("Could not fetch markets for legacy scan: %s — scan skipped", e)
         scan_markets = []
-    await run_legacy_scan(db, scan_markets, manifold, executor, PAPER_MODE)
+    await run_legacy_scan(db, scan_markets, executor, PAPER_MODE)
 
     try:
         await run_trading_loop(poly, external, strategy, risk, executor, metrics, db)