fix(schematics): handle PMC download countdown page and ZIP-wrapped schematics

The download pipeline was getting HTML instead of the binary file because
PMC's /download/schematic/ returns a countdown confirmation page. Added
downloadSchematic() that uses a full browser flow (project visit → download
page → extract static URL → capture file). Also added ZIP extraction via
adm-zip for schematics wrapped in ZIP archives.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -10,6 +10,7 @@
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.27.1",
+    "adm-zip": "^0.5.16",
     "express": "^4.21.2",
     "minecraft-data": "^3.105.0",
     "playwright": "^1.58.2",