fix(demo): correct path resolution for ghostty-web package

The findGhosttyWeb() function was incorrectly resolving the package root
path. The regex /[/\\]dist[/\\].*$/ already strips the path down to
the package root (e.g., '/path/to/node_modules/ghostty-web'), but then
path.dirname() was called which removed one more directory level,
resulting in '/path/to/node_modules' instead.

This caused the 'Could not find ghostty-web package' error when running
npx @ghostty-web/demo because it was looking for the WASM file and dist
folder in node_modules/ instead of node_modules/ghostty-web/.

Fixes the issue where npx @ghostty-web/demo@next fails with:
  Error: Could not find ghostty-web package.

Author: sreya

demo/bin/demo.js

@@ -43,7 +43,8 @@ function findGhosttyWeb() {
   // Use require.resolve to find the installed ghostty-web package
   try {
     const ghosttyWebMain = require.resolve('ghostty-web');
-    const ghosttyWebRoot = path.dirname(ghosttyWebMain.replace(/[/\\]dist[/\\].*$/, ''));
+    // Strip dist/... from path to get package root (regex already gives us the root)
+    const ghosttyWebRoot = ghosttyWebMain.replace(/[/\\]dist[/\\].*$/, '');
     const distPath = path.join(ghosttyWebRoot, 'dist');
     const wasmPath = path.join(ghosttyWebRoot, 'ghostty-vt.wasm');