fix(selection): render gold brick chart as TDX brick blocks with strong-red flag

Match the ZXB1 sub-chart formula: each brick spans between yesterday's
and today's brick value via a stacked range bar — rising bricks are
hollow red (solid on strong_red), falling bricks solid green. The chart
API now also returns brick_strong_red per point.

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

@@ -37,6 +37,7 @@ class SelectionChartPoint:
     trend_white: float | None
     trend_yellow: float | None
     brick_chart: float | None = None
+    brick_strong_red: bool | None = None
 
 
 @dataclass(frozen=True, slots=True)
@@ -95,7 +96,7 @@ 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
+        brick = self._compute_brick_indicators(ts_code, bars) if include_brick_chart else None
         start = max(0, len(bars) - SELECTION_CHART_LIMIT)
         points = tuple(
             SelectionChartPoint(
@@ -111,7 +112,10 @@ class GetSelectionChart:
                 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])
+                    None if brick is None else _finite_or_none(brick["brick_chart"].iloc[index])
+                ),
+                brick_strong_red=(
+                    None if brick is None else _strong_red_or_none(brick["strong_red"].iloc[index])
                 ),
             )
             for index, bar in enumerate(bars)
@@ -125,11 +129,11 @@ class GetSelectionChart:
             points=points,
         )
 
-    def _compute_brick_chart(
+    def _compute_brick_indicators(
         self,
         ts_code: str,
         bars: tuple[SelectionBar, ...],
-    ) -> pd.Series:
+    ) -> pd.DataFrame:
         """Run the gold-brick formula on full history for stable warmup values."""
 
         frame = pd.DataFrame(
@@ -142,7 +146,16 @@ class GetSelectionChart:
                 "volume": [bar.volume for bar in bars],
             }
         )
-        return prepare_gold_brick_indicators(frame, ts_code)["brick_chart"]
+        prepared = prepare_gold_brick_indicators(frame, ts_code)
+        return prepared[["brick_chart", "strong_red"]]
+
+
+def _strong_red_or_none(value: object) -> bool | None:
+    """Convert one Pandas scalar to a JSON-safe brick flag or ``None``."""
+
+    if value is None or pd.isna(value):
+        return None
+    return bool(value)
 
 
 def _finite_or_none(value: object) -> float | None:

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

@@ -167,6 +167,7 @@ class SelectionChartPointResponse(BaseModel):
     trend_white: float | None
     trend_yellow: float | None
     brick_chart: float | None = None
+    brick_strong_red: bool | None = None
 
 
 class SelectionChartResponse(BaseModel):
@@ -510,6 +511,7 @@ def _chart_response(chart: SelectionChart) -> SelectionChartResponse:
                 trend_white=point.trend_white,
                 trend_yellow=point.trend_yellow,
                 brick_chart=point.brick_chart,
+                brick_strong_red=point.brick_strong_red,
             )
             for point in chart.points
         ],