Improve consistency and organization of examples for AI learning

- Add `.gitignore` files to all 19 examples (`node_modules/`, `dist/`)
- Replace custom `log` objects with standard `console` methods
- Add `ontoolcancelled` handler to all `basic-server-*` examples
- Add host styling integration (`applyDocumentTheme`, `applyHostFonts`,
  `applyHostStyleVariables`) to non-React `basic-server-*` examples
- Add section headers for better code organization in feature examples
- Update READMEs with Build System section explaining single-file
  bundling

These changes make examples more consistent and easier to adapt.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

examples/threejs-server/server.ts

@@ -16,6 +16,10 @@ import path from "node:path";
 import { z } from "zod";
 import { startServer } from "./server-utils.js";
 
+// =============================================================================
+// Constants
+// =============================================================================
+
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
 // Default code example for the Three.js widget
@@ -135,6 +139,10 @@ animate();
 
 const resourceUri = "ui://threejs/mcp-app.html";
 
+// =============================================================================
+// Server Setup
+// =============================================================================
+
 /**
  * Creates a new MCP server instance with tools and resources registered.
  * Each HTTP session needs its own server instance because McpServer only supports one transport.