Add workflow_dispatch trigger and fix path filter

Allows manual triggering via GitHub UI/CLI. Also adds the workflow
file itself to the paths filter so changes to it re-trigger a deploy.

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

Author: kanwalnainsingh

.github/workflows/deploy_pages.yml

@@ -1,11 +1,13 @@
 name: Deploy to GitHub Pages
 
 on:
+  workflow_dispatch:
   push:
     branches:
       - main
     paths:
       - 'code_base/web-ui/**'
+      - '.github/workflows/deploy_pages.yml'
 
 permissions:
   contents: write