feat(ui): replace gameplay icons with local SVGs

docs/UI_STYLE.md

@@ -30,10 +30,11 @@ roles must remain stable:
 - black or near-black for the application and map background;
 - purple for panels and elevated surfaces;
 - turquoise for interactive accents;
-- blue for Player 1 and pink for Player 2 across every screen, map object, and
-  message;
-- green for success, yellow for warnings, red for errors, blue for pause, and
-  orange for disconnection;
+- yellow for Player 1 and blue for Player 2 across every screen, map object,
+  and message; each player's matching key and exit use the same ownership
+  color;
+- green for success, amber for warnings, red for errors, periwinkle for pause,
+  and orange for disconnection;
 - green vegetation, bushes, and plants for maze walls.
 
 When two semantic roles use related colors, icons, labels, outlines, or shapes
@@ -41,6 +42,11 @@ must keep them unambiguous. Important player and object information must not be
 communicated by color alone. Key objects use an additional label, outline, or
 marker.
 
+The gameplay icon family is locally authored SVG artwork derived from the
+approved running-player, key, arched-exit, crystal, opened-exit, and spike
+reference silhouettes. The spike icon communicates only blocked movement or a
+wall collision; it never represents a trap or a new gameplay mechanic.
+
 WCAG AA contrast certification and dedicated color-vision-deficiency palettes
 are not MVP requirements.