[feat][backend] add offline metrics

[kidkidkid]

What type of PR is this?

Check the PR title

• This PR title match the format: [<type>][<scope>] <description>. For example: [fix][backend] flaky fix
• The description of this PR title is user-oriented and clear enough for others to understand.
• Add documentation if the current PR requires user awareness at the usage level.
• This PR is written in English. PRs not in English will not be reviewed.

(Optional) Translate the PR title into Chinese

(Optional) More detailed description for this PR(en: English/zh: Chinese)

en:
zh(optional):

(Optional) Which issue(s) this PR fixes

[codecov]

Codecov Report

❌ Patch coverage is 18.60130% with 1129 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ervability/domain/metric/service/offline_metric.go	0.00%	248 Missing ⚠️
...ules/observability/domain/metric/service/metric.go	52.67%	87 Missing and 19 partials ⚠️
...ice/metric/model/model_total_error_count_metric.go	0.00%	33 Missing ⚠️
...e/metric/model/model_total_success_count_metric.go	0.00%	33 Missing ⚠️
...rvice/metric/tool/tool_total_error_count_metric.go	0.00%	33 Missing ⚠️
...ice/metric/tool/tool_total_success_count_metric.go	0.00%	33 Missing ⚠️
...c/service/metric/model/model_total_count_metric.go	0.00%	27 Missing ⚠️
.../metric/service/service_span_error_count_metric.go	0.00%	27 Missing ⚠️
...etric/service/service_span_success_count_metric.go	0.00%	27 Missing ⚠️
...metric/service/service_trace_error_count_metric.go	0.00%	27 Missing ⚠️
... and 68 more

❌ Your patch check has failed because the patch coverage (18.60%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

@@            Coverage Diff             @@
##             main     #326      +/-   ##
==========================================
- Coverage   69.46%   67.73%   -1.74%     
==========================================
  Files         588      609      +21     
  Lines       55149    56297    +1148     
==========================================
- Hits        38310    38132     -178     
- Misses      13940    15253    +1313     
- Partials     2899     2912      +13     

Flag	Coverage Δ
unittests	67.73% <18.60%> (-1.74%)	⬇️

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

Files with missing lines	Coverage Δ
...dules/observability/domain/metric/entity/metric.go	100.00% <ø> (ø)
.../observability/infra/mq/producer/trace_producer.go	88.52% <100.00%> (ø)
backend/modules/observability/infra/repo/trace.go	65.75% <ø> (-0.21%)	⬇️
...tric/service/metric/model/model_duration_metric.go	93.54% <33.33%> (-6.46%)	⬇️
...n/metric/service/metric/model/model_ttft_metric.go	93.33% <0.00%> (-6.67%)	⬇️
.../service/metric/service/service_duration_metric.go	93.33% <0.00%> (-6.67%)	⬇️
...metric/service/metric/tool/tool_duration_metric.go	95.00% <33.33%> (-5.00%)	⬇️
.../metric/service/metric/wrapper/multiple_wrapper.go	0.00% <0.00%> (ø)
...main/metric/service/metric/wrapper/self_wrapper.go	22.22% <0.00%> (-2.78%)	⬇️
...etric/general/general_model_total_tokens_metric.go	88.46% <0.00%> (-11.54%)	⬇️
... and 71 more

... and 4 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1a8aa3c...d074ff4. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.