Feat: Add Organization Subscription-Preview Endpoint

[sbrown-livefront]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-39927

📔 Objective

First endpoint on the new Bit.Subscriptions.Organization feature library and first consumer of the shared, Stripe-invoice-preview–driven cart summary. Sources the organization's upcoming-renewal cart totals from an actual Stripe invoice preview instead of reconstructing them from local subscription state.

Adds:

• GetSubscriptionPreviewQuery (Bit.Invoicing) — shared, ISubscriber-generic query ported from GetBitwardenSubscriptionQuery. Resolves tier/cadence (collapsing TeamsStarter → Teams), previews via create_preview(subscription=id), falls back to the subscription overload when there's no upcoming invoice, and maps subscription status → SubscriptionPreview envelope (suspension/grace-period/cancel). Registered in AddInvoicing(). The Organization path is fully wired here; the User/Premium path is stubbed for Task 8.
• GET /organizations/{organizationId:guid}/billing/subscription/preview — new route on the org subscription group, gated behind PM36631_PreviewDrivenCart.
• Authorization via AuthorizeAttribute<OrganizationBillingRequirement> using the IOrganizationRequirement framework (Owner or confirmed provider-user-for-org; excludes Admin/Custom). Lives entirely in the OrganizationAuthorization library — no dependency on the Api project.
• Unit tests for the query, the requirement, and the endpoint handler + group wiring.

[codecov]

Codecov Report

❌ Patch coverage is 87.61905% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 63.69%. Comparing base (17a1912) to head (ae3f392).

Files with missing lines	Patch %	Lines
...icePreviews/Queries/GetSubscriptionPreviewQuery.cs	85.54%	9 Missing and 3 partials ⚠️
...ion/OrganizationSubscriptionEndpointsExtensions.cs	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8245      +/-   ##
==========================================
+ Coverage   63.67%   63.69%   +0.02%     
==========================================
  Files        2467     2470       +3     
  Lines      105693   105798     +105     
  Branches     9551     9562      +11     
==========================================
+ Hits        67295    67388      +93     
- Misses      36082    36091       +9     
- Partials     2316     2319       +3     

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[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

Reviewed the incremental changes since the last round: the Bit.Invoicing README dependency-table correction, three merges from main, and the PAM using swap to Bit.OrganizationAuthorization. Re-verified the GetSubscriptionPreviewQuery status/tier mapping and Stripe fallback path, the OrganizationBillingRequirement authorization (Owner or confirmed provider user, enforced at the group level), the handler's NotFoundException paths against WithBasicExceptionHandling, and the DI registrations. Confirmed every call site of AuthorizeAttribute<T> carries the new namespace after the move, and that all seven packages.lock.json files referencing subscriptions.organization were regenerated for the new OrganizationAuthorization project reference (project references only — no new or upgraded NuGet packages).

No new findings. The two carried-over items remain as previously acknowledged cleanup-task work: OrganizationBillingRequirement duplicating ManageOrganizationBillingRequirement, and the OrganizationAuthorization library's remaining files still declaring the Bit.Api.AdminConsole.Authorization namespace.

[BTreston]

Approved for AC changes

The base branch was changed.

[amorask-bitwarden]

Looks great, nice work.

[Hinton]

Pam is just namespace change.