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

[Ma77Ball]

What changes were proposed in this PR?

Workflow metrics through the gateway plus an ECharts-based UI panel.
Backend:

• Metrics query builder and parseMetrics.
• MetricsResource serving a closed allowlist of named queries (throughput, outcome rates, and duration percentiles), enforced on both the gateway and the client.
  Frontend:
• Metrics panel rendering each named query as a typed series with Apache ECharts. Chart data is bound as typed arrays; backend output is never interpreted as a formatter or template.

Any related issues, documentation, or discussions?

Closes: #5372
Part of #4070. Stacked on #5379.

How was this PR tested?

• Backend specs for the metrics query builder and parser; sbt scalafmtCheckAll passes.
• Frontend metrics-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 61.02341% with 716 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.33%. Comparing base (6d31f46) to head (18def0e).
⚠️ Report is 52 commits behind head on main.

Files with missing lines	Patch %	Lines
...observability/gateway/ObservabilityResources.scala	0.00%	241 Missing ⚠️
...observability/logs-panel/logs-panel.component.html	56.71%	58 Missing ⚠️
...ala/org/apache/texera/observability/OtelInit.scala	63.30%	43 Missing and 8 partials ⚠️
...apache/texera/web/observability/gateway/dtos.scala	73.40%	44 Missing and 6 partials ⚠️
...texera/web/observability/gateway/AuditLogger.scala	0.00%	41 Missing ⚠️
...xera/web/observability/gateway/ScopeResolver.scala	19.44%	27 Missing and 2 partials ⚠️
...era/web/observability/gateway/GatewayContext.scala	0.00%	21 Missing ⚠️
...ra/web/observability/gateway/ResponseParsers.scala	77.27%	9 Missing and 11 partials ⚠️
...web/observability/gateway/WorkflowRunCounter.scala	0.00%	20 Missing ⚠️
...a/org/apache/texera/web/TexeraWebApplication.scala	0.00%	17 Missing ⚠️
... and 27 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5380      +/-   ##
============================================
+ Coverage     53.86%   55.33%   +1.46%     
- Complexity     2756     3020     +264     
============================================
  Files          1099     1147      +48     
  Lines         42541    44898    +2357     
  Branches       4577     4985     +408     
============================================
+ Hits          22916    24845    +1929     
- Misses        18290    18570     +280     
- Partials       1335     1483     +148     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.14% <100.00%> (-0.30%)	⬇️
agent-service	34.36% <ø> (ø)		Carriedforward from 1a81c33
amber	57.25% <55.31%> (+2.05%)	⬆️
computing-unit-managing-service	0.00% <0.00%> (-1.66%)	⬇️
config-service	50.76% <40.00%> (-5.95%)	⬇️
file-service	58.88% <68.96%> (+1.81%)	⬆️
frontend	49.61% <76.88%> (+1.55%)	⬆️
notebook-migration-service	78.57% <ø> (?)
pyamber	90.15% <100.00%> (+0.02%)	⬆️	Carriedforward from 1a81c33
python	90.76% <ø> (-0.04%)	⬇️	Carriedforward from 1a81c33
workflow-compiling-service	54.74% <ø> (-3.96%)	⬇️

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

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[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @bobbai00, @aicam, @Yicong-Huang
  You can notify them by mentioning @bobbai00, @aicam, @Yicong-Huang in a comment.