docs: remove modes from sidebar navigation

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Co-Authored-By: opencode <noreply@opencode.ai>

packages/web/astro.config.mjs

@@ -75,7 +75,6 @@ export default defineConfig({
         {
           label: "Configure",
           items: [
-            "docs/modes",
             "docs/rules",
             "docs/agents",
             "docs/models",