fix: fix bun install bug (#62)

* fix: fix bun install bug

* refactor: consolidate executable check into assertExecutable helper

- Add assertExecutable() to cli-shared that checks and attempts chmod
- Simplify CLI and SDK spawn code to use the shared helper
- Fix cli-shared package.json exports (.js not .mjs)
- Add global install instructions to SDK error message

* chore(release): update version to 0.1.6-rc.1

* fix: add cli-shared package to Dockerfiles

* chore(release): update version to 0.1.6-rc.1

* fix: add cli-shared publishing to release workflow

* chore(release): update version to 0.1.6-rc.1

* fix: handle already-exists error during crate publish

* chore(release): update version to 0.1.6-rc.1

sdks/cli-shared/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "@sandbox-agent/cli-shared",
+  "version": "0.1.6-rc.1",
+  "description": "Shared helpers for sandbox-agent CLI and SDK",
+  "license": "Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/rivet-dev/sandbox-agent"
+  },
+  "type": "module",
+  "scripts": {
+    "build": "tsup",
+    "typecheck": "tsc --noEmit"
+  },
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "require": "./dist/index.cjs"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "devDependencies": {
+    "@types/node": "^22.0.0",
+    "tsup": "^8.0.0",
+    "typescript": "^5.7.0"
+  }
+}