[PM-30101] add multiple coupon support to server preview/purchase

[kdenney]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-30101

📔 Objective

Added support for multiple coupons for the preview invoice and purchase flows for premium and family (orgs).

[claude]

Claude finished @kdenney's task in 2m 59s —— View job

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Code Review: PM-30101 Multiple Coupon Support

• Gather context and read changed files
• Analyze code changes
• Post review findings

Overall Assessment: Approve

Reviewed the full diff across all 22 changed files. The PR cleanly refactors the billing discount system from single-coupon (string? Coupon) to multi-coupon (string[]? Coupons) support across preview and purchase flows for both premium and organization subscriptions.

Key observations:

• API request models consistently updated across all four entry points
• Core services (SubscriptionDiscountService, OrganizationBillingService, premium commands) properly handle the array with null/empty guards
• Preview flows use graceful fallback (log warning + continue without discounts) while purchase flows use fail-fast validation — appropriate distinction
• Previous review findings have been addressed (dead IsDiscountActive method removed)
• Test coverage is thorough with new multi-coupon test cases across all affected commands

No new issues found. The implementation is consistent and well-tested.

[github-actions]

Checkmarx One – Scan Summary & Details – 6798acc0-4700-41b9-bff0-9bf5930e085c

Great job! No new security vulnerabilities introduced in this pull request

[codecov]

Codecov Report

❌ Patch coverage is 90.58824% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.64%. Comparing base (a7259df) to head (df1658c).

Files with missing lines	Patch %	Lines
...st/Organizations/OrganizationCreateRequestModel.cs	0.00%	2 Missing ⚠️
...zations/OrganizationSubscriptionPurchaseRequest.cs	0.00%	2 Missing ⚠️
...s/Premium/PremiumCloudHostedSubscriptionRequest.cs	0.00%	2 Missing ⚠️
...ce/PreviewPremiumSubscriptionPurchaseTaxRequest.cs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7229      +/-   ##
==========================================
+ Coverage   57.62%   57.64%   +0.01%     
==========================================
  Files        2032     2032              
  Lines       89517    89542      +25     
  Branches     7974     7973       -1     
==========================================
+ Hits        51587    51617      +30     
+ Misses      36071    36070       -1     
+ Partials     1859     1855       -4     

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[cyprain-okeke]

Looks Good

[cyprain-okeke]

Looks great, Please fix the conflict.

[sonarqubecloud]

Quality Gate passed

Issues
37 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