[PM-33500] - delete attachments from deleted ciphers

[jaasen-livefront]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-33500

📔 Objective

Fix orphaned attachment files left behind when ciphers are deleted in bulk, an organization vault is purged, or an organization is deleted.

When a single cipher is deleted via CipherService.DeleteAsync, attachment files are properly removed from blob/disk storage via DeleteAttachmentsForCipherAsync. However, three other deletion paths only removed DB records, leaving attachment files permanently orphaned in storage:

1. CipherService.DeleteManyAsync (bulk cipher delete) — deleted cipher rows but never cleaned up attachment storage.
2. CipherService.PurgeAsync (org vault purge) — deleted cipher rows but never cleaned up attachment storage.
3. OrganizationDeleteCommand.DeleteAsync (org deletion) — cascade-deleted cipher rows via SQL stored proc but never cleaned up attachment storage.

Changes

• CipherService.DeleteManyAsync: After DB deletion, iterate deleted ciphers and call DeleteAttachmentsForCipherAsync for each.
• CipherService.PurgeAsync: Fetch org cipher IDs before DB deletion, then clean up each cipher's attachments after.
• OrganizationDeleteCommand.DeleteAsync: Inject ICipherRepository and IAttachmentStorageService. Fetch org cipher IDs before DB cascade delete, then clean up each cipher's attachments after.
• Updated unit tests for DeleteManyAsync (org admin + personal owner paths) and OrganizationDeleteCommand.Delete_Success to assert attachment cleanup. Added new PurgeAsync_WithOrganizationId_DeletesCiphersAndAttachments test.

📸 Screenshots

[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

[github-actions]

Checkmarx One – Scan Summary & Details – dd616c24-57ab-4f53-ba42-d5b485b10e43

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 57.46%. Comparing base (8688cfc) to head (fe0f808).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7208      +/-   ##
==========================================
+ Coverage   57.44%   57.46%   +0.01%     
==========================================
  Files        2032     2032              
  Lines       89410    89428      +18     
  Branches     7951     7954       +3     
==========================================
+ Hits        51366    51388      +22     
+ Misses      36201    36196       -5     
- Partials     1843     1844       +1     

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