Add bundling support.

- This can now be invoked with `npm run bundle`, it creates a `bundle/` folder that has:
  - gemini.js
  - sandbox-macos-minimal.sb
  - sandbox-macos-strict.sb
  - shell.json
  - shell.md

- This doesn't include any sort of automation for auto bundling pieces. It's just the root capability which we can weave into other locations.

Fixes https://b.corp.google.com/issues/411432723

scripts/copy_bundle_assets.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+# Create the bundle directory if it doesn't exist
+mkdir -p bundle
+
+# Copy specific shell files to the root of the bundle directory
+cp "packages/server/src/tools/shell.md" "bundle/shell.md"
+cp "packages/server/src/tools/shell.json" "bundle/shell.json"
+
+# Find and copy all .sb files from packages to the root of the bundle directory
+find packages -name '*.sb' -exec cp -f {} bundle/ \;
+
+echo "Assets copied to bundle/"