Use proper OpenCode icon

src/icons.ts

@@ -0,0 +1,14 @@
+import { addIcon } from "obsidian";
+
+export const OPENCODE_ICON_NAME = "opencode-logo";
+
+// Monochrome OpenCode "O" logo mark derived from the official brand assets
+// Uses currentColor for theme compatibility
+const OPENCODE_LOGO_SVG = `<svg viewBox="0 0 24 30" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <path d="M18 24H6V12H18V24Z" fill="currentColor" opacity="0.4"/>
+  <path d="M18 6H6V24H18V6ZM24 30H0V0H24V30Z" fill="currentColor"/>
+</svg>`;
+
+export function registerOpenCodeIcons(): void {
+  addIcon(OPENCODE_ICON_NAME, OPENCODE_LOGO_SVG);
+}