feat(@lilith/bitch): Add installer script

Adds install.sh for easy global installation via curl pipe or direct execution.

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

install.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Installer for @lilith/bitch CLI
+# Usage: curl -fsSL <url>/install.sh | bash
+
+set -euo pipefail
+
+REGISTRY="http://forge.nasty.sh/api/packages/lilith/npm/"
+PACKAGE="@lilith/bitch"
+
+echo "Installing $PACKAGE globally..."
+
+# Detect package manager
+if command -v pnpm &>/dev/null; then
+    pnpm add -g "$PACKAGE" --registry "$REGISTRY"
+elif command -v npm &>/dev/null; then
+    npm install -g "$PACKAGE" --registry "$REGISTRY"
+else
+    echo "Error: No package manager found (pnpm or npm required)"
+    exit 1
+fi
+
+echo "✓ Installed. Run 'bitch --help' to get started."