feat(cli): extract Obelisk runtime into npm package

Add @obelisk-apps/cli with the existing build, search, query, and attune contract plus official skill installation.

Separate the docs-only skill artifact, bootstrap installer, release layout, cross-platform CI, and package-level regression coverage.

install.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+set -eu
+
+PACKAGE='@obelisk-apps/cli'
+
+if ! command -v node >/dev/null 2>&1; then
+  echo 'Obelisk requires Node.js 22.13 or newer.' >&2
+  exit 1
+fi
+
+if ! node -e "const [major, minor] = process.versions.node.split('.').map(Number); process.exit(major > 22 || (major === 22 && minor >= 13) ? 0 : 1)"; then
+  echo 'Obelisk requires Node.js 22.13 or newer.' >&2
+  exit 1
+fi
+
+if ! command -v npm >/dev/null 2>&1; then
+  echo 'Obelisk installation requires npm.' >&2
+  exit 1
+fi
+
+echo "Installing ${PACKAGE}..."
+npm install --global "$PACKAGE"
+
+if ! command -v obelisk >/dev/null 2>&1; then
+  echo 'The CLI was installed, but `obelisk` is not on PATH.' >&2
+  echo 'Add the npm global bin directory to PATH, then run `obelisk --version`.' >&2
+  exit 1
+fi
+
+obelisk --version
+echo 'Obelisk CLI installed. Run `obelisk install` to install the agent skill.'