Implement P1 local matcher/ledger and P2 strategy engine.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/strategy/exits.py

@@ -0,0 +1,23 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(slots=True)
+class ExitDecision:
+    should_close: bool
+    reason: str = ""
+
+
+def check_exits(
+    *,
+    perp_upl: float,
+    initial_premium: float,
+    move_points: float,
+    exit_move_points: float,
+) -> ExitDecision:
+    if initial_premium > 0 and perp_upl + 1e-9 >= initial_premium:
+        return ExitDecision(True, "premium_cover")
+    if exit_move_points > 0 and move_points + 1e-9 >= exit_move_points:
+        return ExitDecision(True, "move_points")
+    return ExitDecision(False, "")