[PM-33894] Schedule price increases

[amorask-bitwarden]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-33894

📔 Objective

Modifies UpcomingInvoiceHandler to defer subscription price changes to the renewal date using Stripe subscription schedules, gated behind the PM32645_DeferPriceMigrationToRenewal feature flag. This fixes MRR distortion caused by the current behavior of updating subscription prices immediately when invoice.upcoming fires (~15 days before renewal).

When the flag is enabled, both the Premium user and Families organization paths now:

• Check for an existing active schedule (idempotency guard)
• Create a 2-phase subscription schedule from the current subscription
• Phase 1 echoes the current subscription state; Phase 2 applies the new price (and discount where applicable) at renewal

When the flag is disabled, existing UpdateSubscription behavior is preserved.

Also migrates UpcomingInvoiceHandler from the legacy IStripeFacade to IStripeAdapter and adds SubscriptionScheduleStatus and SubscriptionScheduleEndBehavior constants to StripeConstants.

[github-actions]

Checkmarx One – Scan Summary & Details – 7ec5e5d6-bff3-4dc8-a983-ce25f2118c6f

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

[codecov]

Codecov Report

❌ Patch coverage is 86.09626% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.87%. Comparing base (4f37c93) to head (d70858c).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...Services/Implementations/UpcomingInvoiceHandler.cs	86.09%	22 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7293      +/-   ##
==========================================
+ Coverage   57.84%   57.87%   +0.02%     
==========================================
  Files        2043     2043              
  Lines       89879    90002     +123     
  Branches     7989     8000      +11     
==========================================
+ Hits        51992    52090      +98     
- Misses      36029    36050      +21     
- Partials     1858     1862       +4     

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[github-actions]

Overall Assessment: APPROVE

This PR introduces deferred price migration via Stripe subscription schedules for both Premium users and Families organizations, gated behind the PM32645_DeferPriceMigrationToRenewal feature flag. The implementation migrates from IStripeFacade to IStripeAdapter, adds a shared SchedulePriceMigrationAsync method with an idempotency guard (checking for existing active schedules) and orphaned schedule cleanup on failure, carries storage items into phase 2, and adds new SubscriptionScheduleStatus and SubscriptionScheduleEndBehavior constants. The legacy path is fully preserved when the flag is disabled. Test coverage is comprehensive with eight new test cases covering schedule creation, idempotency, error handling, and edge cases.

Code Review Details

No findings to report. The implementation is well-structured with appropriate error handling, idempotency guards, and feature flag gating.

[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