feat: Add skip_copilot_assignment input (#598)

Part of
github/continuous-ai-for-accessibility#20
(Hubber access only)

Implements @kendallgassner’s boolean input suggestion[^1] from
https://github.slack.com/archives/C096E0MSFFY/p1758141682789409?thread_ts=1758136571.223419&cid=C096E0MSFFY
(Hubber access only)

This PR adds a new optional input to the main composite scanner action
named `skip_copilot_assignment`:
- If provided and set to exactly `true` (a lowercase string, no leading
or trailing whitespace), then the ‘Fix’ step is skipped.
- If omitted, or if set to any other value (including `True`, `TRUE`,
`yes`, `false`, etc.), then the ‘Fix’ step is _not_ skipped.

If a workflow uses `skip_copilot_assignment: true`, Copilot can still be
assigned _manually_ (or by other automations) to issues opened by that
workflow.

[^1]: With a small difference: This PR uses underscores, to match the
style of the other inputs.

Author: smockle

README.md

@@ -96,6 +96,7 @@ Trigger the workflow manually or automatically based on your configuration. The
 | `repository` | Yes | Repository (with owner) for issues and PRs | `primer/primer-docs` |
 | `token` | Yes | PAT with write permissions (see above) | `${{ secrets.GH_TOKEN }}` |
 | `cache_key` | No | Custom key for caching findings across runs<br>Allowed: `A-Za-z0-9._/-` | `cached_findings-main-primer.style.json` |
+| `skip_copilot_assignment` | No | Whether to skip assigning filed issues to Copilot | `true` |
 
 ---
 

action.yml

@@ -15,6 +15,10 @@ inputs:
   cache_key:
     description: "Custom key for caching findings across runs"
     required: false
+  skip_copilot_assignment:
+    description: "Whether to skip assigning filed issues to Copilot"
+    required: false
+    default: "false"
 
 runs:
   using: "composite"
@@ -48,7 +52,8 @@ runs:
         repository: ${{ inputs.repository }}
         token: ${{ inputs.token }}
         cached_findings: ${{ steps.restore.outputs.value }}
-    - name: Fix
+    - if: ${{ inputs.skip_copilot_assignment != 'true' }}
+      name: Fix
       id: fix
       uses: ./.github/actions/fix
       with: