feat(integration): add Pinterest click ID capture (epik/_epik)

[jciafardone]

Add Pinterest epik and _epik parameter mapping to integrationMappingExternal.

• Added epik parameter mapping to capture Pinterest click IDs
• Added _epik parameter mapping to capture Pinterest click IDs
• Both map to Pinterest.click_id in custom flags
• Supports capture from query parameters, cookies, and localStorage
• Reference: https://developers.pinterest.com/docs/track-conversions/track-conversions-in-the-api/

Testing:

• Added comprehensive tests covering both epik and _epik variants
• Tests verify capture from all three sources (query params, cookies, localStorage)
• Tests verify proper mapping to custom flags

Background

• Pinterest uses both epik (query parameter) and _epik (cookie) to track click IDs
• The epik parameter is appended by Pinterest to ad click URLs
• The _epik cookie is stored by Pinterest's tag
• Both variants need to be captured to ensure comprehensive click ID tracking
• Pinterest requires the click ID to be sent as Pinterest.click_id custom flag for Pinterest Conversions API (CAPI) integration
• Currently, the SDK captures click IDs for Facebook, Google, TikTok, and Snapchat, but not Pinterest
• This change adds Pinterest to the list of supported integration-specific identifier captures

What Has Changed

• Added epik parameter mapping to integrationMappingExternal in integrationCapture.ts
• Added _epik parameter mapping to integrationMappingExternal in integrationCapture.ts
• Both epik and _epik map to Pinterest.click_id custom flag
• Each parameter variant is checked in all three sources:
  • Query parameters (e.g., ?epik=value or ?_epik=value)
  • Cookies (e.g., epik=value or _epik=value)
  • localStorage (e.g., localStorage.getItem('epik') or localStorage.getItem('_epik'))
• Follows standard priority resolution: query params > localStorage > cookies
• Outputs to CUSTOM_FLAGS (consistent with other click ID integrations like gclid, fbclid, ttclid)
• No processor function needed (unlike Facebook's fbclid which requires formatting)

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

• Tested extraction logic locally using standalone browser test file
• Verified capture from URL query params, cookies, and localStorage for both epik and _epik variants
• Confirmed priority resolution works correctly (query > localStorage > cookie)
• Validated custom flag mapping to Pinterest.click_id
• Verified that when both variants are present, both map to the same custom flag key
• This change is additive and does not affect existing integrations
• No breaking changes introduced

[rmi22186]

@jciafardone - looks like @alexs-mparticle 's comment here still hasn't been updated- 2dfa771#r2607709893

is his docs link correct? If so, please update.

[rmi22186]

@jciafardone there's also some conflicts now, can you resolve, commit, and force push to this branch?

[rmi22186]

hit approve too soon. left one coment @jciafardone

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud