fix(resolution): cast $3 explicitly in close_paper_position and persist before mutating portfolio

Cycle-10 resolution check found market 562186 resolved (Paxton YES) but the
close failed with asyncpg AmbiguousParameterError: Postgres cannot infer the
type of a bare '$3 IS NOT NULL' in the close_pnl CASE. Reproduced via PREPARE
in the postgres pod; fixed by casting every $3 use to double precision.

The failed DB write also left memory/DB diverged: close_position() popped the
position and credited cash before persisting, so the retry at cycle 20 skipped
the market (pnl=n/a) while the DB row stayed open. Now the DB write happens
first and memory mutates only on success; check_resolutions() also isolates
per-market close failures so one error doesn't abort the cycle.

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

bot/executor/paper.py

@@ -245,7 +245,7 @@ class PaperExecutor:
         if market_id not in self._portfolio.positions:
             return None
 
-        position_cost = self._portfolio.positions.pop(market_id)
+        position_cost = self._portfolio.positions[market_id]
         open_trades = await self._db.get_open_trades_for_market(market_id)
 
         if open_trades:
@@ -266,13 +266,17 @@ class PaperExecutor:
             payout = position_cost
             pnl = 0.0
 
-        self._portfolio.cash += payout
-
+        # Persist first, mutate memory after: if the DB write fails, the
+        # in-memory portfolio must keep the position so the next resolution
+        # check can retry the close.
         await self._db.close_paper_position(
             market_id,
             reason="resolved",
             resolution=resolution,
         )
+
+        self._portfolio.positions.pop(market_id)
+        self._portfolio.cash += payout
         log.info(
             "Closed position in %s, resolution=%.1f payout=$%.2f pnl=%+.2f",
             market_id, resolution, payout, pnl,