feat(selection): show gold brick chart below volume in stock detail panel

Add an optional brick_chart series to the selection chart API, computed
from the shared gold-brick formula when strategy=gold_brick, and render
a fourth grid with red/green brick bars between the volume and J grids.

zhixing-server/src/zhixing_server/modules/selection/application/chart.py

@@ -9,7 +9,9 @@ from typing import Literal, cast
 
 import pandas as pd
 
+from ..domain.gold_brick import prepare_gold_brick_indicators
 from ..domain.indicators import compute_kdj, compute_zhixing_lines
+from ..domain.models import SelectionBar
 from ..domain.ports import MarketDataReader
 
 SELECTION_CHART_LIMIT = 250
@@ -21,7 +23,7 @@ class SelectionChartNotFound(LookupError):
 
 @dataclass(frozen=True, slots=True)
 class SelectionChartPoint:
-    """One date-aligned OHLCV, KDJ, and Zhixing-line point."""
+    """One date-aligned OHLCV, KDJ, Zhixing-line, and gold-brick point."""
 
     trade_date: date
     open: float | None
@@ -34,6 +36,7 @@ class SelectionChartPoint:
     j: float | None
     trend_white: float | None
     trend_yellow: float | None
+    brick_chart: float | None = None
 
 
 @dataclass(frozen=True, slots=True)
@@ -55,12 +58,18 @@ class GetSelectionChart:
 
         self.reader = reader
 
-    def execute(self, ts_code: str, target_trade_date: date) -> SelectionChart:
+    def execute(
+        self,
+        ts_code: str,
+        target_trade_date: date,
+        include_brick_chart: bool = False,
+    ) -> SelectionChart:
         """Return at most 250 points without changing full-history indicator state.
 
         Args:
             ts_code: Tushare stock identifier selected by the user.
             target_trade_date: Inclusive historical boundary for the chart.
+            include_brick_chart: Compute the gold-brick series for the request.
 
         Returns:
             An ascending qfq chart series aligned by trade date.
@@ -86,6 +95,7 @@ class GetSelectionChart:
         )
         kdj = compute_kdj(frame)
         white, yellow = compute_zhixing_lines(frame["close"])
+        brick_chart = self._compute_brick_chart(ts_code, bars) if include_brick_chart else None
         start = max(0, len(bars) - SELECTION_CHART_LIMIT)
         points = tuple(
             SelectionChartPoint(
@@ -100,6 +110,9 @@ class GetSelectionChart:
                 j=_finite_or_none(kdj.iloc[index]["J"]),
                 trend_white=_finite_or_none(white.iloc[index]),
                 trend_yellow=_finite_or_none(yellow.iloc[index]),
+                brick_chart=(
+                    None if brick_chart is None else _finite_or_none(brick_chart.iloc[index])
+                ),
             )
             for index, bar in enumerate(bars)
             if index >= start
@@ -112,6 +125,25 @@ class GetSelectionChart:
             points=points,
         )
 
+    def _compute_brick_chart(
+        self,
+        ts_code: str,
+        bars: tuple[SelectionBar, ...],
+    ) -> pd.Series:
+        """Run the gold-brick formula on full history for stable warmup values."""
+
+        frame = pd.DataFrame(
+            {
+                "trade_date": [bar.trade_date for bar in bars],
+                "open": [bar.open for bar in bars],
+                "high": [bar.high for bar in bars],
+                "low": [bar.low for bar in bars],
+                "close": [bar.close for bar in bars],
+                "volume": [bar.volume for bar in bars],
+            }
+        )
+        return prepare_gold_brick_indicators(frame, ts_code)["brick_chart"]
+
 
 def _finite_or_none(value: object) -> float | None:
     """Convert one Pandas scalar to a finite JSON-safe float or ``None``."""

zhixing-server/src/zhixing_server/modules/selection/presentation/http.py

@@ -153,7 +153,7 @@ class SelectionStockResponse(BaseModel):
 
 
 class SelectionChartPointResponse(BaseModel):
-    """One date-aligned qfq OHLCV, KDJ, and Zhixing-line point."""
+    """One date-aligned qfq OHLCV, KDJ, Zhixing-line, and gold-brick point."""
 
     trade_date: date
     open: float | None
@@ -166,6 +166,7 @@ class SelectionChartPointResponse(BaseModel):
     j: float | None
     trend_white: float | None
     trend_yellow: float | None
+    brick_chart: float | None = None
 
 
 class SelectionChartResponse(BaseModel):
@@ -276,11 +277,16 @@ def get_selection_chart(
     ts_code: str,
     target_trade_date: date,
     service: Annotated[GetSelectionChart, Depends(get_selection_chart_service)],
+    strategy: StrategyValue = "zhixing_b1",
 ) -> SelectionChartResponse:
     """Return one stock's bounded qfq OHLCV, KDJ, and Zhixing-line history."""
 
     try:
-        chart = service.execute(ts_code, target_trade_date)
+        chart = service.execute(
+            ts_code,
+            target_trade_date,
+            include_brick_chart=strategy == "gold_brick",
+        )
     except SelectionChartNotFound as exc:
         raise _http_error(404, "chart_data_not_found", str(exc)) from exc
     except MarketDataReaderError as exc:
@@ -503,6 +509,7 @@ def _chart_response(chart: SelectionChart) -> SelectionChartResponse:
                 j=point.j,
                 trend_white=point.trend_white,
                 trend_yellow=point.trend_yellow,
+                brick_chart=point.brick_chart,
             )
             for point in chart.points
         ],