fix(npm): download binaries during postinstall

The npm package was missing the actual binary download step - users got
wrapper scripts pointing to non-existent binaries.

Changes:
- postinstall.js now downloads correct binary from GitHub releases
- Added vestige.js wrapper for CLI binary
- Exposed both vestige-mcp and vestige commands in package.json
- Updated README with troubleshooting, storage info, CLI docs
- Added .gitignore for downloaded binaries

Fixes fresh install issues where Claude Desktop couldn't attach and
vestige CLI wasn't found.

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

packages/vestige-mcp-npm/package.json

@@ -1,9 +1,10 @@
 {
   "name": "@vestige/mcp",
-  "version": "0.1.0",
+  "version": "1.1.0",
   "description": "Vestige MCP Server - AI Memory System for Claude and other assistants",
   "bin": {
-    "vestige-mcp": "./bin/vestige-mcp.js"
+    "vestige-mcp": "./bin/vestige-mcp.js",
+    "vestige": "./bin/vestige.js"
   },
   "scripts": {
     "postinstall": "node scripts/postinstall.js"