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 63.75610% with 743 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.20%. Comparing base (7e9cabf) to head (fed8677).
⚠️ Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
...observability/gateway/ObservabilityResources.scala	0.00%	192 Missing ⚠️
...nt/user/list-item/card-item/card-item.component.ts	47.23%	76 Missing and 10 partials ⚠️
...observability/logs-panel/logs-panel.component.html	56.92%	55 Missing and 1 partial ⚠️
...apache/texera/web/observability/gateway/dtos.scala	72.25%	46 Missing and 7 partials ⚠️
...ala/org/apache/texera/observability/OtelInit.scala	63.30%	43 Missing and 8 partials ⚠️
...texera/web/observability/gateway/AuditLogger.scala	0.00%	41 Missing ⚠️
.../user/list-item/card-item/card-item.component.html	56.52%	38 Missing and 2 partials ⚠️
...xera/web/observability/gateway/ScopeResolver.scala	19.44%	27 Missing and 2 partials ⚠️
...era/web/observability/gateway/GatewayContext.scala	0.00%	19 Missing ⚠️
...a/org/apache/texera/web/TexeraWebApplication.scala	0.00%	16 Missing ⚠️
... and 27 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5380      +/-   ##
============================================
+ Coverage     52.87%   53.20%   +0.32%     
- Complexity     2509     2663     +154     
============================================
  Files          1073     1118      +45     
  Lines         41382    43731    +2349     
  Branches       4444     4834     +390     
============================================
+ Hits          21882    23268    +1386     
- Misses        18214    19078     +864     
- Partials       1286     1385      +99     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.91% <100.00%> (+6.30%)	⬆️
agent-service	34.36% <ø> (ø)		Carriedforward from ffe8f80
amber	53.14% <60.64%> (-0.46%)	⬇️
computing-unit-managing-service	1.65% <ø> (ø)
config-service	56.71% <ø> (ø)
file-service	57.06% <ø> (ø)
frontend	48.65% <68.55%> (+1.35%)	⬆️
pyamber	90.73% <100.00%> (+0.01%)	⬆️	Carriedforward from ffe8f80
python	90.73% <ø> (-0.03%)	⬇️	Carriedforward from ffe8f80
workflow-compiling-service	58.69% <ø> (ø)

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

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[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 5 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main b8859b4 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	378	0.23	26,974/36,021/36,021 us	🔴 +32.5% / 🔴 +13.4%
🟢	bs=100 sw=10 sl=64	813	0.496	120,431/145,230/145,230 us	🟢 -7.8% / 🔴 -8.9%
⚪	bs=1000 sw=10 sl=64	933	0.57	1,074,293/1,111,252/1,111,252 us	⚪ within ±5% / 🔴 -10.4%

Baseline details

Latest main b8859b4 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	378 tuples/sec	441 tuples/sec	410.82 tuples/sec	-14.3%	-8.0%
bs=10 sw=10 sl=64	MB/s	0.23 MB/s	0.269 MB/s	0.251 MB/s	-14.5%	-8.3%
bs=10 sw=10 sl=64	p50	26,974 us	20,357 us	23,785 us	+32.5%	+13.4%
bs=10 sw=10 sl=64	p95	36,021 us	32,326 us	34,980 us	+11.4%	+3.0%
bs=10 sw=10 sl=64	p99	36,021 us	32,326 us	34,980 us	+11.4%	+3.0%
bs=100 sw=10 sl=64	throughput	813 tuples/sec	823 tuples/sec	891.94 tuples/sec	-1.2%	-8.9%
bs=100 sw=10 sl=64	MB/s	0.496 MB/s	0.502 MB/s	0.544 MB/s	-1.2%	-8.9%
bs=100 sw=10 sl=64	p50	120,431 us	117,281 us	112,277 us	+2.7%	+7.3%
bs=100 sw=10 sl=64	p95	145,230 us	157,595 us	139,802 us	-7.8%	+3.9%
bs=100 sw=10 sl=64	p99	145,230 us	157,595 us	139,802 us	-7.8%	+3.9%
bs=1000 sw=10 sl=64	throughput	933 tuples/sec	946 tuples/sec	1,041 tuples/sec	-1.4%	-10.4%
bs=1000 sw=10 sl=64	MB/s	0.57 MB/s	0.577 MB/s	0.635 MB/s	-1.2%	-10.3%
bs=1000 sw=10 sl=64	p50	1,074,293 us	1,053,290 us	972,714 us	+2.0%	+10.4%
bs=1000 sw=10 sl=64	p95	1,111,252 us	1,100,641 us	1,023,057 us	+1.0%	+8.6%
bs=1000 sw=10 sl=64	p99	1,111,252 us	1,100,641 us	1,023,057 us	+1.0%	+8.6%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,529.78,200,128000,378,0.230,26974.38,36021.43,36021.43
1,100,10,64,20,2460.35,2000,1280000,813,0.496,120430.60,145230.19,145230.19
2,1000,10,64,20,21434.13,20000,12800000,933,0.570,1074293.48,1111251.73,1111251.73