fix card gradients and AI Pick tag alignment

Use a theme-qualified tab gradient start color in both AI Pick and market ranking so the fade no longer introduces a white tint in dark mode.

Add light and dark resource variants, and wrap AI Pick strategy tags in a fixed-height centered container while preserving single-line ellipsis behavior.

src/main/resources/base/element/color.json

@@ -52,6 +52,10 @@
       "name": "transparent_white",
       "value": "#00FFFFFF"
     },
+    {
+      "name": "tab_gradient_start",
+      "value": "#00FFFFFF"
+    },
     {
       "name": "color_333333",
       "value": "#333333"

src/main/resources/dark/element/color.json

@@ -7,6 +7,10 @@
     {
       "name": "solid_grey_900",
       "value": "#3B3B3B"
+    },
+    {
+      "name": "tab_gradient_start",
+      "value": "#00000000"
     }
   ]
 }