chore(frontend, amber): remove the unreachable available-result event and orphaned list item

[aglinxinyuan]

What changes were proposed in this PR?

Removes three unreachable pieces of code. 998 lines deleted, 1 added.

1. WorkflowAvailableResultEvent and its dangling client handler. Nothing in src/main constructs the event, and it is not among the 11 classOf[...] entries in TexeraWebSocketEvent.scala's @JsonSubTypes, so it is not reflectively dispatched either. Yet workflow-result.service.ts still subscribed to "WorkflowAvailableResultEvent" and routed it to handleCleanResultCache — a handler the backend could never trigger.

A second signal that this path was never live: the TypeScript type declared availableOperators as ReadonlyArray<OperatorAvailableResult>, while both the Scala event and the handler treat it as a keyed map (Map[String, OperatorAvailableResult] / Object.entries(...)). The declared wire shape matched neither producer nor consumer.

Removed: the Scala event, the frontend subscription, handleCleanResultCache, the orphaned TS types and their TexeraWebsocketEventTypeMap entry, and a then-unused WebOutputMode import.

2. UserDatasetListItemComponent is orphaned. Its selector appears repo-wide only in its own @Component declaration and its own spec's test host. The single other reference was a standalone entry in app.module.ts's imports array with no consumer — and since declarations is [AppComponent] only, being in imports merely exposes it to AppComponent's template, where the selector does not appear. The dataset page moved to texera-card-item/texera-search-results in #5947.

Checked beyond the selector, because a component can be reached indirectly: only two @NgModules exist in the app, no loadChildren/loadComponent lazy routes reference it, and there is no createComponent/ngComponentOutlet/ComponentFactoryResolver instantiation.

Removed the .ts, .html, .scss, its spec, and both app.module.ts lines.

3. DynamicSchemaService.dynamicSchemaExists — exactly one occurrence repo-wide, its own declaration, while every sibling method has 2 to 5 call sites.

Two tests were removed, deliberately

Two cases in workflow-result.service.spec.ts existed solely to exercise handleCleanResultCache, by pushing a synthetic event directly onto the socket subject. Their own fixtures are corroborating evidence: they pass availableOperators as a keyed object — matching the Scala type and the handler — while the declared TS type said array. They could not have been written from a real frame.

The user-dataset-list-item spec went with its component for the same reason.

A stale scaladoc paragraph in TexeraWebSocketEventSpec.scala also named this event, noting that "nothing in main constructs it, so pinning its wire shape would only cement dead code" — an independent confirmation of the finding from an earlier reviewer. That paragraph is removed; the preceding one, which lists the five genuinely unregistered producers, stays accurate. No count or reflection assertion depended on it.

Verification

• Full frontend suite: 200 files, 4708 passed, 1 skipped, 0 failed.
• Amber TexeraWebSocketEventSpec: main and test compiled with no errors, 10/10 passed. Compiling clean is itself the proof that nothing in amber referenced the deleted class.
• AOT ng build succeeded — this matters, because ng test and tsc --noEmit both miss Angular template errors, so a removed component could otherwise break the build silently. Bundle generation completed with zero NG#### diagnostics and zero errors referencing src/. The build's exit code is 1 from exactly the 13 pre-existing monaco webpack loader failures on node_modules assets, which are unrelated to this change.
• yarn format:ci exits 0; scalafmtCheck, Test/scalafmtCheck and scalafixAll --check all pass — no imports were left orphaned.
• Residual-reference greps for both removed symbols come back empty.

Any related issues, documentation, discussions?

Closes #7782

How was this PR tested?

npx ng test --watch=false

 Test Files  200 passed (200)
      Tests  4708 passed | 1 skipped (4709)

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Generated-by: Claude Code (Opus 5)

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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: @Neilk1021, @kunwp1, @Ma77Ball
  You can notify them by mentioning @Neilk1021, @kunwp1, @Ma77Ball in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.25%. Comparing base (bf0e777) to head (173fe37).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##               main    #7783    +/-   ##
==========================================
  Coverage     91.24%   91.25%            
- Complexity     4468     4470     +2     
==========================================
  Files          1171     1168     -3     
  Lines         47115    46987   -128     
  Branches       5286     5271    -15     
==========================================
- Hits          42991    42878   -113     
+ Misses         2448     2436    -12     
+ Partials       1676     1673     -3     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from bf0e777
agent-service	98.62% <ø> (ø)		Carriedforward from bf0e777
amber	88.03% <ø> (+0.04%)	⬆️
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from bf0e777
config-service	86.73% <ø> (ø)		Carriedforward from bf0e777
file-service	68.90% <ø> (ø)		Carriedforward from bf0e777
frontend	92.62% <ø> (-0.02%)	⬇️
notebook-migration-service	83.74% <ø> (ø)		Carriedforward from bf0e777
pyamber	97.57% <ø> (ø)		Carriedforward from bf0e777
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from bf0e777

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

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[github-actions]

✅ No material benchmark regressions detected

🟢 5 better · 🔴 0 worse · ⚪ 10 noise (<±5%) · 0 without baseline

Compared against main bf0e777 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	794	0.485	12,259/15,835/15,835 us	🟢 -12.3% / 🟢 -20.3%
🟢	bs=100 sw=10 sl=64	1,808	1.104	55,608/61,488/61,488 us	🟢 -24.2% / 🟢 +88.5%
⚪	bs=1000 sw=10 sl=64	2,057	1.256	480,637/545,746/545,746 us	⚪ within ±5% / 🟢 +106.9%

Baseline details

Latest main bf0e777 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	794 tuples/sec	765 tuples/sec	743.3 tuples/sec	+3.8%	+6.8%
bs=10 sw=10 sl=64	MB/s	0.485 MB/s	0.467 MB/s	0.454 MB/s	+3.9%	+6.9%
bs=10 sw=10 sl=64	p50	12,259 us	13,140 us	13,204 us	-6.7%	-7.2%
bs=10 sw=10 sl=64	p95	15,835 us	18,051 us	16,220 us	-12.3%	-2.4%
bs=10 sw=10 sl=64	p99	15,835 us	18,051 us	19,867 us	-12.3%	-20.3%
bs=100 sw=10 sl=64	throughput	1,808 tuples/sec	1,786 tuples/sec	959.52 tuples/sec	+1.2%	+88.4%
bs=100 sw=10 sl=64	MB/s	1.104 MB/s	1.09 MB/s	0.586 MB/s	+1.3%	+88.5%
bs=100 sw=10 sl=64	p50	55,608 us	53,052 us	103,974 us	+4.8%	-46.5%
bs=100 sw=10 sl=64	p95	61,488 us	81,132 us	111,036 us	-24.2%	-44.6%
bs=100 sw=10 sl=64	p99	61,488 us	81,132 us	118,982 us	-24.2%	-48.3%
bs=1000 sw=10 sl=64	throughput	2,057 tuples/sec	2,027 tuples/sec	994.68 tuples/sec	+1.5%	+106.8%
bs=1000 sw=10 sl=64	MB/s	1.256 MB/s	1.237 MB/s	0.607 MB/s	+1.5%	+106.9%
bs=1000 sw=10 sl=64	p50	480,637 us	485,754 us	1,011,206 us	-1.1%	-52.5%
bs=1000 sw=10 sl=64	p95	545,746 us	557,925 us	1,055,603 us	-2.2%	-48.3%
bs=1000 sw=10 sl=64	p99	545,746 us	557,925 us	1,084,808 us	-2.2%	-49.7%

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
0,10,10,64,20,251.82,200,128000,794,0.485,12258.97,15835.05,15835.05
1,100,10,64,20,1105.97,2000,1280000,1808,1.104,55607.53,61487.81,61487.81
2,1000,10,64,20,9721.86,20000,12800000,2057,1.256,480636.59,545745.51,545745.51