[PM-34429] Create an endpoint to retrieve the InviteBlob

[JimmyVo16]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-38794

📔 Objective

1. Add an endpoint to retrieve the invite blob.
2. Use orgId to get the invite blob.
3. Validations:
   1. Invite link exists
   2. Request code matches database code
   3. Org has the UseInviteLinks ability
4. Exclude from validations
   1. Policies
   2. Existing org user
5. Add unit and integration tests.
6. Feature flag for Milestone 1.

[codecov]

Codecov Report

❌ Patch coverage is 91.11111% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 62.06%. Comparing base (74ffe65) to head (55c4496).

Files with missing lines	Patch %	Lines
...Console/Controllers/OrganizationUsersController.cs	81.25%	2 Missing and 1 partial ⚠️
...es/InviteLinks/GetOrganizationInviteBlobRequest.cs	75.00%	1 Missing ⚠️

Additional details and impacted files

@@                             Coverage Diff                             @@
##           pm-40216/data-protect-invite-link-codes    #7994      +/-   ##
===========================================================================
- Coverage                                    66.61%   62.06%   -4.56%     
===========================================================================
  Files                                         2277     2281       +4     
  Lines                                        99556    99600      +44     
  Branches                                      8990     8995       +5     
===========================================================================
- Hits                                         66323    61817    -4506     
- Misses                                       30961    35608    +4647     
+ Partials                                      2272     2175      -97     

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[github-actions]

🤖 Bitwarden Claude Code Review

Overall Assessment: APPROVE

Reviewed the new GetInviteBlob endpoint and GetOrganizationInviteBlobCommand, which retrieve an organization's opaque invite blob after validating the invite link, organization ability, and email domain. The implementation mirrors the existing Accept/Confirm/Status invite-link commands, uses constant-time code comparison, and returns InviteLinkNotFound uniformly for both missing links and code mismatches to avoid enumeration. Zero-knowledge is preserved: the blob is transported opaquely and decrypted client-side. Unit and integration tests cover all validation branches.

Code Review Details

No findings. The change follows established patterns: CommandResult error mapping via the base controller Handle, TryAddScoped DI registration, nullable reference types, and the RequireFeature(GenerateInviteLink) gate consistent with sibling endpoints. The prior review's dangling doc-comment suggestion was addressed.