fix: align production defaults and close review parity gaps

Ship greenfield min_rr=2.0 and conf=0, read-only Structural S/R, indicator
cache invalidation, and UI/gate language that treats GTL as screening not exit.
Align strategy_rank missing-vol fallback live vs backtest, single-source
PRIMARY_TARGET_MIN_RR, expand prod parity tests, and drop dead FE clients.

app/services/sr_service.py

@@ -857,8 +857,17 @@ async def get_sr_levels(
     symbol: str,
     tolerance: float | None = None,
 ) -> list[SRLevel]:
-    """Get S/R levels for a ticker, recalculating on every request (MVP).
+    """Return persisted Structural S/R levels, strength descending.
 
-    Returns levels sorted by strength descending.
+    Read-only: does not recompute or rewrite. Pipeline/ingestion call
+    ``recalculate_sr_levels`` to refresh. ``tolerance`` is kept for API
+    compatibility and ignored on read (it only applies at recalculation).
     """
-    return await recalculate_sr_levels(db, symbol, tolerance)
+    del tolerance  # API compat only; levels were stored at last recalculation
+    ticker = await _get_ticker(db, symbol)
+    result = await db.execute(
+        select(SRLevel)
+        .where(SRLevel.ticker_id == ticker.id)
+        .order_by(SRLevel.strength.desc())
+    )
+    return list(result.scalars().all())