[task] Extract `sanitizeLabelContent` to dedicated helper file

[github-actions]

Objective

Extract the duplicate sanitizeLabelContent function from create_issue.cjs and add_labels.cjs into a dedicated helper file that can be imported individually.

Context

The sanitizeLabelContent function appears identically in two files (100% duplicate, 14 lines). Following the pattern of "1 javascript helper per file so that they can be imported one by one", this function should be extracted to its own module. Part of issue #3119.

Approach

1. Create new file: pkg/workflow/js/sanitize_label_content.cjs
2. Move the sanitizeLabelContent function to this new file
3. Export the function as a CommonJS module: module.exports = { sanitizeLabelContent };
4. Update pkg/workflow/js/create_issue.cjs to import: const { sanitizeLabelContent } = require('./sanitize_label_content.cjs');
5. Update pkg/workflow/js/add_labels.cjs to import: const { sanitizeLabelContent } = require('./sanitize_label_content.cjs');
6. Remove the duplicate function definitions from both files

Files to Modify

• Create: pkg/workflow/js/sanitize_label_content.cjs (new helper file)
• Update: pkg/workflow/js/create_issue.cjs (import and remove duplicate)
• Update: pkg/workflow/js/add_labels.cjs (import and remove duplicate)

Acceptance Criteria

• New helper file sanitize_label_content.cjs contains the function
• Function is properly exported as CommonJS module
• Both create_issue.cjs and add_labels.cjs import from the new helper
• No duplicate function definitions remain
• Existing tests pass (no functionality broken)
• Code follows the pattern: 1 helper per file for granular imports
  Related to [refactor] 🔧 Semantic Function Clustering Analysis: Refactoring Opportunities #3119

AI generated by Plan Command for #3119