feat(cli): add release workflow, install scripts, and self-update command

Replace the npm-only publish-cli.yml with a comprehensive release-cli.yml
that builds standalone binaries via pkg for all platforms (Linux/macOS/Windows,
x64/arm64), uploads them as GitHub Release assets with SHA256 checksums,
and retains npm publish as an optional job.

Add curl-pipe-sh installer (install.sh) and PowerShell installer (install.ps1)
for one-liner installation from GitHub Releases. Both scripts auto-detect
platform/architecture, verify checksums, and guide PATH configuration.

Add `game-ci update` command for self-updating standalone binaries: checks
GitHub releases for newer versions, downloads the correct platform binary,
verifies it, and atomically replaces the running executable.

Distribution strategy: GitHub Releases (primary), npm (optional), with
winget/Homebrew/Chocolatey/Scoop as future providers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -6,6 +6,21 @@
   "bin": {
     "game-ci": "./lib/cli.js"
   },
+  "pkg": {
+    "scripts": "lib/**/*.js",
+    "assets": [
+      "lib/**/*.json",
+      "package.json"
+    ],
+    "targets": [
+      "node20-linux-x64",
+      "node20-linux-arm64",
+      "node20-macos-x64",
+      "node20-macos-arm64",
+      "node20-win-x64"
+    ],
+    "outputPath": "dist-binaries"
+  },
   "repository": "git@github.com:game-ci/unity-builder.git",
   "author": "Webber <webber@takken.io>",
   "license": "MIT",
@@ -83,6 +98,7 @@
     "js-yaml": "^4.1.0",
     "lefthook": "^1.6.1",
     "node-fetch": "2",
+    "pkg": "^5.8.1",
     "prettier": "^2.5.1",
     "ts-jest": "^27.1.3",
     "ts-node": "10.8.1",