Fix Players page KeyError + use_container_width deprecation

- Players page: fix regression_chart xg_col default (goals_p90 -> xg_p90)
- charts.py: make regression_chart defensive against missing columns
- All pages: replace use_container_width=True with width='stretch'
- Verified: all 5 pages render with zero errors via Playwright browser test

dashboard/viz/charts.py

@@ -112,15 +112,18 @@ def percentile_radar(player_row: pd.Series, metrics: list, labels: list,
 # ─────────────────────────────────────────────────────────────────
 
 def regression_chart(df: pd.DataFrame, player: str,
-                     xg_col="goals_p90", goal_col="goals_season",
+                     xg_col="xg_p90", goal_col="goals_season",
                      games_col="games_season") -> go.Figure:
-    """Rolling actual goals vs expected with divergence shading.
-    Uses season-level totals as static chart.
-    """
+    """Rolling actual goals vs expected with divergence shading."""
+    actual = df[goal_col].iloc[0] if goal_col in df.columns else 0
+    xg_val = df[xg_col].iloc[0] if xg_col in df.columns else 0
+    games = df[games_col].iloc[0] if games_col in df.columns else 1
+    expected = xg_val * 1.2 * games
+
     fig = go.Figure()
     fig.add_trace(go.Bar(
         x=["Actual Goals", "Expected (xG * 1.2)"],
-        y=[df[goal_col].iloc[0], df[xg_col].iloc[0] * 1.2 * df[games_col].iloc[0]],
+        y=[actual, expected],
         marker_color=[PITCH_GREEN, SKY], texttemplate="%{y:.1f}",
         textposition="outside", textfont=dict(color=TEXT, size=13),
         showlegend=False,