Fix post annotations lost on direct publish

[ruibaby]

What type of PR is this?

• Feature
• Bug fix
• Improvement
• Cleanup
• Documentation

What this PR does / why we need it:

Syncs the post annotation form before publishing from the post settings modal. This makes direct publish use the same metadata collection path as Save, so a new unsaved post keeps the metadata configured in the publish flow.

Adds regression coverage for direct publish from PostSettingModal.

Which issue(s) this PR fixes:

Fixes #7420

Special notes for your reviewer:

Implemented with AI assistance and reviewed before submission.

Does this PR introduce a user-facing change?

修复首次发布文章时，设置的元数据可能出现没有保存的问题

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 61.95%. Comparing base (42c374d) to head (5893237).
⚠️ Report is 652 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #10114      +/-   ##
============================================
+ Coverage     59.55%   61.95%   +2.39%     
- Complexity     3812     4245     +433     
============================================
  Files           677      713      +36     
  Lines         23248    24398    +1150     
  Branches       1500     1623     +123     
============================================
+ Hits          13846    15116    +1270     
+ Misses         8764     8508     -256     
- Partials        638      774     +136     

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[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