fix: preserve keyword markers in themes for default export configuration

[ankita10119]

🔧 Changes

Fixes keyword preservation for themes when AUTH0_EXPORT_IDENTIFIERS is false (the default configuration).

Root cause: ThemesHandler used identifiers: ['themeId'] to match local theme entries during keyword preservation. However, themeId is stripped from exported files by default (AUTH0_EXPORT_IDENTIFIERS: false), so the preservation logic could never find a matching identifier and silently skipped preservation, causing keyword markers
like ##CDN_URL## to be overwritten with raw values on re-export.

Changes:

• ThemesHandler: Added displayName as a secondary identifier alongside themeId, providing a match path for users who have named their theme but do not use AUTH0_EXPORT_IDENTIFIERS
• getPreservableFieldsFromAssets in keywordPreservation.ts:
  • Fixed the identifier reduce to skip missing identifiers instead of resetting the accumulator, allowing multi-identifier fallback to work correctly
  • Added positional index fallback when registered identifiers are absent from the local file, safe for themes since Auth0 supports only one theme per tenant

📚 References

• Related: Fix: a0deploy keyword replacement mappings not applied to theme.json  #1379 (partial fix - only covered AUTH0_EXPORT_IDENTIFIERS: true)

🔬 Testing

Unit tests added covering the following scenarios:

1. themeId present in local file (AUTH0_EXPORT_IDENTIFIERS: true) - preserved via themeId identifier
2. displayName present but not themeId - preserved via displayName identifier
3. Neither themeId nor displayName present (default export, exact customer scenario) - preserved via positional index fallback
4. identifiers: [] (no identifiers registered for array type) - NOT preserved, confirming the fallback does not apply to unrecognized arrays

Manual end-to-end test:

1. Set AUTH0_PRESERVE_KEYWORDS: false in config, run export to get a baseline tenant.yaml
2. Edit tenant.yaml - replace raw URLs with quoted keyword markers e.g. font_url: '##CDN_URL##/fonts/custom.woff2'
3. Set AUTH0_PRESERVE_KEYWORDS: true, re-run export
4. Confirm tenant.yaml still contains ##CDN_URL## markers instead of resolved URLs

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.84%. Comparing base (eb215ab) to head (d1ec576).

Files with missing lines	Patch %	Lines
src/keywordPreservation.ts	71.42%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1387      +/-   ##
==========================================
- Coverage   79.84%   79.84%   -0.01%     
==========================================
  Files         153      153              
  Lines        7052     7056       +4     
  Branches     1547     1549       +2     
==========================================
+ Hits         5631     5634       +3     
  Misses        781      781              
- Partials      640      641       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.