feat(ui): replace gameplay icons with local SVGs

docs/PLAYER_UI.md

@@ -12,6 +12,20 @@ locally authored `icons.svg` sprite. The deterministic asset build compresses
 each file with gzip for LittleFS. There are no remote fonts, frameworks,
 analytics, icon services, or runtime network dependencies beyond the local ESP.
 
+## Gameplay icon mapping
+
+`icons.svg` contains editable, local SVG symbols with a shared `64 x 64` view
+box for the reference-derived gameplay set: `player`, `key`, `exit-closed`,
+`crystal`, `exit-open`, and `spikes`. Player 1 is yellow and Player 2 is blue;
+their matching keys and exits use the same owner color. The player, key, and
+exit silhouettes remain distinct, and Player 2 uses a dashed secondary
+treatment so ownership does not depend on color alone.
+
+The closed and opened arched exits show the existing locked and opened exit
+states. The crystal represents the existing vision artifact. Spikes appear only
+with local blocked-movement feedback and do not add a trap, damage, protocol,
+or server-state feature.
+
 ## Input contract
 
 Arrow keys and WASD map to `north`, `east`, `south`, and `west` move intentions.

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.