Remove unnecessary workflow_call trigger from actionci (#1584)

* Remove unnecessary workflow_call trigger from actionci caller workflow

* Remove redundant zizmor.yml workflow

The actionci.yml workflow already calls zizmor as a sub-workflow via
smallstep/workflows, so a separate zizmor.yml is unnecessary.

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: tashian

.github/workflows/actionci.yml

@@ -7,7 +7,6 @@ on:
     branches:
     - "master"
   pull_request:
-  workflow_call:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}