[PM-40533] feat: Validate recipient email domains against SendControls allowed domains

[andrebispo5]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-40533

📔 Objective

When an org's SendControls policy sets allowedDomains, saving a Send with Specific people
recipients now checks each recipient's domain against that list, and blocks the save with an error
dialog if any of them falls outside it.

What changed

• The check runs at save time in handleSaveClick, right after the existing email format
  validation, so it does not fire on every keystroke
• Error dialog reuses the existing "Invalid email addresses" title, with a new description listing
  the allowed domains
• The policy value arrives as one comma-separated string, so it gets trimmed and emptied of blanks
  before both matching and display. Domain matching is case-insensitive
• A policy value with nothing usable in it, "," for example, counts as no restriction. Failing
  closed there would block saving with no way for the user to recover

Scope

• Only applies when Who can view is Specific people, since that is the only case with recipients.
  Other access types are untouched
• Flag off or no domains configured means no domain checking at all, and the existing format
  validation is unaffected either way

Note for reviewers

This stacks on #7266 (PM-40531), so please review that one first. The diff here is only the last
three commits.

📸 Screenshots

Before	After

[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 86.20%. Comparing base (af5320d) to head (0ff6ab5).

Files with missing lines	Patch %	Lines
...tools/feature/send/addedit/AddEditSendViewModel.kt	94.11%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@                             Coverage Diff                              @@
##           PM-40531-lock-who-can-view-when-enforced    #7269      +/-   ##
============================================================================
+ Coverage                                     85.93%   86.20%   +0.27%     
============================================================================
  Files                                           937      894      -43     
  Lines                                         67225    65371    -1854     
  Branches                                       9861     9826      -35     
============================================================================
- Hits                                          57769    56354    -1415     
+ Misses                                         5937     5513     -424     
+ Partials                                       3519     3504      -15     

Flag	Coverage Δ
app-data	17.86% <0.00%> (+0.33%)	⬆️
app-ui-auth-tools	18.81% <94.11%> (+<0.01%)	⬆️
app-ui-platform	16.40% <0.00%> (-0.49%)	⬇️
app-ui-vault	27.30% <0.00%> (-0.55%)	⬇️
authenticator	6.08% <0.00%> (-0.01%)	⬇️
lib-core-network-bridge	4.09% <0.00%> (-0.01%)	⬇️
lib-data-ui	1.20% <0.00%> (-0.01%)	⬇️

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