fix(api): compute history aggregates across all matches

[KyleTryon]

Summary

• execute full-query aggregate statistics for history responses instead of using only the current page
• compute popular extractors with grouped database results across all matching rows
• add a pagination regression test that keeps totals stable with limit=1

Validation

• uv run black app/api/v1/endpoints/history.py tests/test_api/test_history.py
• uv run ruff check app/api/v1/endpoints/history.py tests/test_api/test_history.py
• uv run pytest tests/test_api/test_history.py tests/test_api/test_timeline.py tests/test_api/test_stats.py

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 49.19%. Comparing base (1ec3045) to head (142cae3).
⚠️ Report is 60 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #95      +/-   ##
==========================================
+ Coverage   40.59%   49.19%   +8.60%     
==========================================
  Files         145      139       -6     
  Lines        7119     6860     -259     
  Branches     1206     1075     -131     
==========================================
+ Hits         2890     3375     +485     
+ Misses       4222     3478     -744     
  Partials        7        7              

Flag	Coverage Δ		*Carryforward flag
backend	65.69% <100.00%> (+8.52%)	⬆️
frontend	31.12% <ø> (+6.78%)	⬆️	Carriedforward from 3130715

*This pull request uses carry forward flags. Click here to find out more.

Components	Coverage Δ
Frontend (hermes-app)	31.12% <71.71%> (+6.78%)	⬆️
Backend (hermes-api)	65.69% <90.90%> (+8.52%)	⬆️

Files with missing lines	Coverage Δ
...ackages/hermes-api/app/api/v1/endpoints/history.py	77.01% <100.00%> (+59.23%)	⬆️

... and 13 files with indirect coverage changes