refactor(amber): rename execution coordinators to managers

[Yicong-Huang]

What changes were proposed in this PR?

Pure mechanical rename of the two region-scheduling classes, freeing the "Coordinator" name for the upcoming Controller → Coordinator rename (#6122):

Before	After
WorkflowExecutionCoordinator	WorkflowExecutionManager
RegionExecutionCoordinator	RegionExecutionManager
RegionCoordinatorTestSupport	RegionExecutionManagerTestSupport

The Manager suffix mirrors the WorkflowExecution / RegionExecution state objects each class owns and drives, following existing precedent (GlobalReplayManager, OutputManager). Variables (workflowExecutionCoordinator, regionExecutionCoordinators, unfinishedRegionCoordinators, …), comments (including two RegionExecutionCoordintor typos), and cross-references in Python comments were updated together. Files moved with git mv; no behavior change.

Any related issues, documentation, discussions?

Closes #6121. Prerequisite for #6122.

How was this PR tested?

Refactor with no behavior change — the existing specs were renamed along with the classes and stay green with no assertion edits:

sbt "WorkflowExecutionService/testOnly org.apache.texera.amber.engine.architecture.scheduling.WorkflowExecutionManagerSpec org.apache.texera.amber.engine.architecture.scheduling.RegionExecutionManagerSpec"

grep -riE 'ExecutionCoordinator|RegionCoordinator|Coordintor' over the repo returns no matches after the rename.

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

Generated-by: Claude Code (Claude Fable 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: @Ma77Ball, @aglinxinyuan, @kunwp1
  You can notify them by mentioning @Ma77Ball, @aglinxinyuan, @kunwp1 in a comment.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.81818% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.13%. Comparing base (908a61f) to head (b6abd55).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
.../promisehandlers/JumpToOperatorRegionHandler.scala	0.00%	2 Missing ⚠️
...chitecture/scheduling/RegionExecutionManager.scala	75.00%	0 Missing and 1 partial ⚠️
...itecture/scheduling/WorkflowExecutionManager.scala	87.50%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #6123   +/-   ##
=========================================
  Coverage     59.12%   59.13%           
- Complexity     3197     3201    +4     
=========================================
  Files          1132     1132           
  Lines         43681    43681           
  Branches       4734     4734           
=========================================
+ Hits          25828    25831    +3     
+ Misses        16419    16418    -1     
+ Partials       1434     1432    -2     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from 908a61f
agent-service	44.59% <ø> (ø)		Carriedforward from 908a61f
amber	63.11% <81.81%> (+0.02%)	⬆️
computing-unit-managing-service	0.00% <ø> (ø)		Carriedforward from 908a61f
config-service	52.30% <ø> (ø)		Carriedforward from 908a61f
file-service	62.81% <ø> (ø)		Carriedforward from 908a61f
frontend	51.37% <ø> (ø)		Carriedforward from 908a61f
notebook-migration-service	78.57% <ø> (ø)		Carriedforward from 908a61f
pyamber	91.14% <ø> (-0.05%)	⬇️
workflow-compiling-service	55.14% <ø> (ø)		Carriedforward from 908a61f

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

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[github-actions]

⚠️ Benchmark changes need a look

🟢 0 better · 🔴 7 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main 6de8a48 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	408	0.249	24,639/34,210/34,210 us	🔴 +22.9% / 🔴 +125.9%
🔴	bs=100 sw=10 sl=64	849	0.518	116,093/138,370/138,370 us	🔴 +8.6% / 🔴 +28.2%
⚪	bs=1000 sw=10 sl=64	956	0.584	1,047,747/1,101,732/1,101,732 us	⚪ within ±5% / 🔴 +7.1%

Baseline details

Latest main 6de8a48 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	408 tuples/sec	460 tuples/sec	776.36 tuples/sec	-11.3%	-47.4%
bs=10 sw=10 sl=64	MB/s	0.249 MB/s	0.281 MB/s	0.474 MB/s	-11.4%	-47.5%
bs=10 sw=10 sl=64	p50	24,639 us	20,041 us	12,636 us	+22.9%	+95.0%
bs=10 sw=10 sl=64	p95	34,210 us	30,043 us	15,143 us	+13.9%	+125.9%
bs=10 sw=10 sl=64	p99	34,210 us	30,043 us	18,954 us	+13.9%	+80.5%
bs=100 sw=10 sl=64	throughput	849 tuples/sec	879 tuples/sec	985.33 tuples/sec	-3.4%	-13.8%
bs=100 sw=10 sl=64	MB/s	0.518 MB/s	0.536 MB/s	0.601 MB/s	-3.4%	-13.9%
bs=100 sw=10 sl=64	p50	116,093 us	112,498 us	101,671 us	+3.2%	+14.2%
bs=100 sw=10 sl=64	p95	138,370 us	127,362 us	107,939 us	+8.6%	+28.2%
bs=100 sw=10 sl=64	p99	138,370 us	127,362 us	113,798 us	+8.6%	+21.6%
bs=1000 sw=10 sl=64	throughput	956 tuples/sec	957 tuples/sec	1,016 tuples/sec	-0.1%	-5.9%
bs=1000 sw=10 sl=64	MB/s	0.584 MB/s	0.584 MB/s	0.62 MB/s	0.0%	-5.9%
bs=1000 sw=10 sl=64	p50	1,047,747 us	1,040,376 us	989,693 us	+0.7%	+5.9%
bs=1000 sw=10 sl=64	p95	1,101,732 us	1,083,800 us	1,028,327 us	+1.7%	+7.1%
bs=1000 sw=10 sl=64	p99	1,101,732 us	1,083,800 us	1,059,969 us	+1.7%	+3.9%

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
0,10,10,64,20,490.04,200,128000,408,0.249,24638.77,34209.88,34209.88
1,100,10,64,20,2354.36,2000,1280000,849,0.518,116092.59,138369.81,138369.81
2,1000,10,64,20,20913.13,20000,12800000,956,0.584,1047746.58,1101731.77,1101731.77