refactor(amber): make the hub and unified search resource-agnostic

[tanishqgandhi1908]

What changes were proposed in this PR?

The hub dispatched on EntityType in four separate places, and DatasetSearchQueryBuilder
carried its own copy of the access-scoped join, the keyword/date/id filter and the
LakeFS-sized hydration. Adding a second resource type meant four dispatch edits plus a
clone of the query logic, and two of those sites compiled cleanly but failed at runtime.

• EntityTables now exposes one EntityTableSet per entity type, with cloneTable as an
  Option and a new AccessTable that removes the non-exhaustive match in
  HubResource.userAccess.
• VersionedResourceTables names the columns of a LakeFS-backed resource;
  VersionedResourceSearchQueryBuilder holds the single copy of FROM / WHERE / hydration.
  DatasetSearchQueryBuilder keeps only its projection.
• The five dataset-only slots in UnifiedResourceSchema become shared versioned-resource
  slots, so the next resource type widens the union by two columns instead of seven.

Two existing bugs are fixed as a result: getTops?entityType=dataset with no actionTypes
no longer 500s on a throwing CloneTable(Dataset), and getCounts' clone guard now asks
whether the entity type has a clone table instead of whether it is not a dataset.

No user-facing behavior changes.

Any related issues, documentation, discussions?

Prepares the amber side of #6501 (part of #6494): adding models becomes one descriptor plus
one registry entry. Contains #6872 and #7922, so their commits show in the diff until they
merge.

How was this PR tested?

Existing suites, unmodified except where they pin the renamed projection aliases:
WorkflowExecutionService/testOnly *dashboard* — 467/467, and FileService/test — 376/376.
New VersionedResourceTablesSpec covers the descriptor contract and the access-join
predicate; EntityTablesSpec covers the registry; regression tests added for the two bugs
above (getTops with no actionTypes, and the clone bucket for a cloneless entity type).

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

Generated-by: Claude Code (Claude Opus 5)

[github-actions]

Automated Reviewer Suggestions

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

• Contributors with relevant context: @aglinxinyuan, @Mrudhulraj, @VuMartin
  You can notify them by mentioning @aglinxinyuan, @Mrudhulraj, @VuMartin in a comment.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 87.50000% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.25%. Comparing base (5de9bf9) to head (fa7fda3).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...exera/web/resource/dashboard/hub/HubResource.scala	33.33%	11 Missing and 1 partial ⚠️
...b/resource/dashboard/VersionedResourceTables.scala	91.42%	1 Missing and 2 partials ⚠️
...ashboard/VersionedResourceSearchQueryBuilder.scala	95.65%	1 Missing ⚠️
...xera/web/resource/dashboard/hub/EntityTables.scala	97.43%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7928      +/-   ##
============================================
+ Coverage     93.22%   93.25%   +0.03%     
+ Complexity     4666     4661       -5     
============================================
  Files          1175     1176       +1     
  Lines         47645    47566      -79     
  Branches       5319     5300      -19     
============================================
- Hits          44417    44358      -59     
+ Misses         1749     1735      -14     
+ Partials       1479     1473       -6     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)		Carriedforward from 34eb44b
agent-service	99.32% <ø> (ø)		Carriedforward from 34eb44b
amber	89.37% <87.50%> (+0.03%)	⬆️
computing-unit-managing-service	73.67% <ø> (ø)		Carriedforward from 34eb44b
config-service	86.73% <ø> (ø)		Carriedforward from 34eb44b
file-service	86.72% <ø> (+0.02%)	⬆️	Carriedforward from 34eb44b
frontend	95.67% <ø> (+<0.01%)	⬆️	Carriedforward from 34eb44b
notebook-migration-service	79.31% <ø> (ø)		Carriedforward from 34eb44b
pyamber	97.78% <ø> (+0.04%)	⬆️	Carriedforward from 34eb44b
workflow-compiling-service	77.19% <ø> (ø)		Carriedforward from 34eb44b

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

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[github-actions]

⚠️ Benchmark changes need a look

🟢 6 better · 🔴 1 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main 5de9bf9 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	563	0.344	17,051/20,933/20,933 us	🟢 -49.4% / 🔴 +56.3%
🟢	bs=100 sw=10 sl=64	1,222	0.746	82,837/94,687/94,687 us	🟢 -18.4% / ⚪ within ±5%
⚪	bs=1000 sw=10 sl=64	1,404	0.857	713,163/764,485/764,485 us	⚪ within ±5% / 🟢 -16.5%

Baseline details

Latest main 5de9bf9 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	563 tuples/sec	501 tuples/sec	908.02 tuples/sec	+12.4%	-38.0%
bs=10 sw=10 sl=64	MB/s	0.344 MB/s	0.306 MB/s	0.554 MB/s	+12.4%	-37.9%
bs=10 sw=10 sl=64	p50	17,051 us	14,730 us	10,907 us	+15.8%	+56.3%
bs=10 sw=10 sl=64	p95	20,933 us	41,331 us	13,604 us	-49.4%	+53.9%
bs=10 sw=10 sl=64	p99	20,933 us	41,331 us	16,697 us	-49.4%	+25.4%
bs=100 sw=10 sl=64	throughput	1,222 tuples/sec	1,250 tuples/sec	1,188 tuples/sec	-2.2%	+2.9%
bs=100 sw=10 sl=64	MB/s	0.746 MB/s	0.763 MB/s	0.725 MB/s	-2.2%	+2.9%
bs=100 sw=10 sl=64	p50	82,837 us	78,895 us	85,003 us	+5.0%	-2.5%
bs=100 sw=10 sl=64	p95	94,687 us	116,081 us	91,599 us	-18.4%	+3.4%
bs=100 sw=10 sl=64	p99	94,687 us	116,081 us	99,202 us	-18.4%	-4.6%
bs=1000 sw=10 sl=64	throughput	1,404 tuples/sec	1,435 tuples/sec	1,221 tuples/sec	-2.2%	+15.0%
bs=1000 sw=10 sl=64	MB/s	0.857 MB/s	0.876 MB/s	0.745 MB/s	-2.2%	+15.0%
bs=1000 sw=10 sl=64	p50	713,163 us	693,725 us	837,593 us	+2.8%	-14.9%
bs=1000 sw=10 sl=64	p95	764,485 us	762,229 us	881,015 us	+0.3%	-13.2%
bs=1000 sw=10 sl=64	p99	764,485 us	762,229 us	915,550 us	+0.3%	-16.5%

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
0,10,10,64,20,355.32,200,128000,563,0.344,17050.72,20933.24,20933.24
1,100,10,64,20,1636.89,2000,1280000,1222,0.746,82836.56,94686.58,94686.58
2,1000,10,64,20,14243.99,20000,12800000,1404,0.857,713162.98,764485.31,764485.31

[tanishqgandhi1908]

/request-review @aicam

[aicam]

LGTM