Add authenticated documentation server

- Created docs_server.py with HTTP basic authentication
- Added start-docs-server.sh for easy startup
- Updated README.md with documentation access instructions
- Provides working authentication when .htaccess isn't supported

Usage: ./start-docs-server.sh [port]
Credentials: langmem / langmem2025

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

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

start-docs-server.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# Start LangMem Documentation Server with Authentication
+
+echo "🚀 Starting LangMem Documentation Server..."
+echo "🔐 Authentication enabled with basic auth"
+echo ""
+
+# Default port
+PORT=${1:-8080}
+
+# Start the authenticated server
+python3 docs_server.py $PORT