[fix][backend] fix backfill filter

[zero3233-bd]

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[codecov]

Codecov Report

❌ Patch coverage is 92.45283% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...y/domain/task/service/taskexe/tracehub/backfill.go	0.00%	2 Missing and 1 partial ⚠️
.../modules/observability/domain/task/entity/event.go	50.00%	0 Missing and 1 partial ⚠️

@@            Coverage Diff             @@
##             main     #318      +/-   ##
==========================================
+ Coverage   68.42%   68.44%   +0.01%     
==========================================
  Files         585      585              
  Lines       54127    54178      +51     
==========================================
+ Hits        37039    37084      +45     
- Misses      14254    14257       +3     
- Partials     2834     2837       +3     

Flag	Coverage Δ
unittests	68.44% <92.45%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...lity/domain/task/service/taskexe/tracehub/utils.go	91.52% <100.00%> (+36.97%)	⬆️
.../modules/observability/domain/task/entity/event.go	45.88% <50.00%> (-0.59%)	⬇️
...y/domain/task/service/taskexe/tracehub/backfill.go	66.78% <0.00%> (-0.74%)	⬇️

... and 1 file with indirect coverage changes

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[CozeLoop]

Automated review completed by Aime: No issues found for backend changes in PR #318.