Enforce adding a message to extension CLI bumps (#58786)

This slightly reworks the extension CLI bump workflow - instead of
triggering on label push, it now triggers on workflow dispatch with a
message enforced to be added there.

This primarily allows us to add a message to these bumps to better
communicate what changes with that version of the CLI. Furthermore, we
can soon restrict the label to be only created by that workflow, which
has the advantage that it can only be based off of main. Also, it has
the nice side-effect that we actually only ever update the label if
everything worked properly.

Release Notes:

- N/A

script/bump-extension-cli

@@ -1,7 +1,34 @@
 #!/usr/bin/env bash
 
-set -e
+set -eu
 
-git pull --ff-only origin main
-git tag -f extension-cli
-git push -f origin extension-cli
+usage() {
+  echo "Usage: $0 <message>"
+  echo ""
+  echo "Triggers the publish_extension_cli workflow on main to build a new"
+  echo "extension CLI binary, bump the 'extension-cli' tag after a successful"
+  echo "build, and open PRs that update the SHA used by the zed and"
+  echo "zed-industries/extensions repositories."
+  echo ""
+  echo "Arguments:"
+  echo "  message    Describes why the extension CLI is being bumped /"
+  echo "             what the changes include. Included in the PR bodies."
+  exit 1
+}
+
+if [[ $# -lt 1 || -z "${1:-}" ]]; then
+  echo "error: a message describing the bump is required" >&2
+  echo "" >&2
+  usage >&2
+fi
+
+which gh > /dev/null 2>&1 || {
+  echo "error: GitHub CLI (gh) is required but not installed." >&2
+  echo "Install it with: brew install gh" >&2
+  exit 1
+}
+
+gh workflow run publish_extension_cli.yml --ref main -f message="$1"
+
+echo "Workflow triggered. Monitor progress at:"
+echo "  https://github.com/zed-industries/zed/actions/workflows/publish_extension_cli.yml"