feat(observability): logs end-to-end (gateway + UI panel)

[Ma77Ball]

What changes were proposed in this PR?

First complete signal: log search through the gateway plus a UI panel to drive it.
Backend:

• Logs query builder and response parsers (parseLogs, parseLogSources), applying per-field redaction.
• LogsResource exposing log search and the source-facets endpoint, registered in TexeraWebApplication.
  Frontend:
• Logs panel with time-window, service, workflow, computing-unit, execution, level, and free-text filters, server-side paging, and sources-backed autofill.

Any related issues, documentation, or discussions?

Closes: #5371
Part of #4070. Stacked on #5378.

How was this PR tested?

• Backend specs for the logs query builder and response parsers; sbt scalafmtCheckAll passes.
• Frontend logs-panel and service specs; prettier-eslint and eslint pass.
• Compile and the full test suites run in this PR's CI.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.8 in compliance with ASF

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.84692% with 50 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.77%. Comparing base (24b587f) to head (76eeb09).
⚠️ Report is 928 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...a/org/apache/texera/web/TexeraWebApplication.scala	0.00%	19 Missing ⚠️
.../engine/architecture/coordinator/Coordinator.scala	68.18%	6 Missing and 1 partial ⚠️
...exera/service/resource/AccessControlResource.scala	70.58%	0 Missing and 5 partials ⚠️
...exera/amber/engine/common/client/ClientActor.scala	77.77%	0 Missing and 2 partials ⚠️
...la/org/apache/texera/web/ComputingUnitMaster.scala	0.00%	2 Missing ⚠️
...org/apache/texera/web/StaticAssetCacheFilter.scala	89.47%	0 Missing and 2 partials ⚠️
...mber/src/main/python/core/models/internal_queue.py	94.44%	0 Missing and 1 partial ⚠️
amber/src/main/python/core/models/operator.py	98.38%	1 Missing ⚠️
amber/src/main/python/core/models/tuple.py	92.85%	0 Missing and 1 partial ⚠️
...hitecture/common/PekkoActorRefMappingService.scala	0.00%	0 Missing and 1 partial ⚠️
... and 9 more

Additional details and impacted files

@@              Coverage Diff              @@
##               main    #5379       +/-   ##
=============================================
+ Coverage     56.89%   69.77%   +12.87%     
- Complexity     3058     3542      +484     
=============================================
  Files          1129     1174       +45     
  Lines         43802    46525     +2723     
  Branches       4743     5685      +942     
=============================================
+ Hits          24922    32463     +7541     
+ Misses        17449    12334     -5115     
- Partials       1431     1728      +297     

Flag	Coverage Δ		*Carryforward flag
access-control-service	80.27% <72.22%> (+10.27%)	⬆️
agent-service	99.32% <100.00%> (+54.73%)	⬆️
amber	66.43% <70.21%> (+7.78%)	⬆️	Carriedforward from fcc8222
computing-unit-managing-service	77.20% <ø> (+77.20%)	⬆️
config-service	87.25% <ø> (+34.94%)	⬆️
file-service	63.84% <ø> (+1.02%)	⬆️	Carriedforward from fcc8222
frontend	60.98% <ø> (+10.85%)	⬆️	Carriedforward from fcc8222
notebook-migration-service	83.73% <ø> (+5.16%)	⬆️
pyamber	98.47% <99.42%> (+7.32%)	⬆️
python	?
workflow-compiling-service	74.25% <ø> (+19.10%)	⬆️

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

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.