fix(examples): resolve DIST_DIR path for npm package execution (#277)

* fix(examples): resolve DIST_DIR path for npm package execution

When servers are compiled to dist/server.js and published to npm,
`import.meta.dirname` already points to dist/, so joining with "dist"
results in dist/dist/ which doesn't exist.

This fix detects whether we're running from TypeScript source or
compiled JavaScript and adjusts the path accordingly:
- From source (server.ts): use dist/ subdirectory
- From compiled (dist/server.js): use current directory

Fixes ENOENT errors like:
"ENOENT: no such file or directory, open '.../dist/dist/mcp-app.html'"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

* fix(pdf-server): mark pdfjs-dist as external in bundle

The pdf.worker.mjs file wasn't being found when running from npm
because bun bundled pdfjs-dist but didn't include the worker file.

By marking pdfjs-dist as external, it uses the installed package
from node_modules at runtime where the worker is available.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

examples/map-server/server.ts

@@ -21,7 +21,10 @@ import {
 } from "@modelcontextprotocol/ext-apps/server";
 import { randomUUID } from "crypto";
 
-const DIST_DIR = path.join(import.meta.dirname, "dist");
+// Works both from source (server.ts) and compiled (dist/server.js)
+const DIST_DIR = import.meta.filename.endsWith(".ts")
+  ? path.join(import.meta.dirname, "dist")
+  : import.meta.dirname;
 const RESOURCE_URI = "ui://cesium-map/mcp-app.html";
 
 // Nominatim API response type