feat: near-close scan schedule and distinct-day gate reset

Move the only qualifying R:R scan to 15:30 ET with chained Telegram alerts,
put outcome eval after a final-bar OHLCV fetch, enforce NY trading-day
requalify semantics, stamp paper trades fill_mode=near_close, and migrate
stored schedule_* keys to America/New_York.

app/schemas/paper_trade.py

@@ -47,6 +47,8 @@ class PaperTradeResponse(BaseModel):
     alpha_pct: float | None = None
     alpha_usd: float | None = None
     close_reason: str | None = None
+    # Execution era: null = pre-cutover / unknown; "near_close" = post schedule cutover.
+    fill_mode: str | None = None
     # Live trailing-stop level + how far price sits above it (% ), for open trades
     # when the trailing exit policy is active.
     trailing_stop: float | None = None