chore: bump main version to 1.4.0-incubating-SNAPSHOT

[mengw15]

What changes were proposed in this PR?

This PR bumps the project version on main from 1.3.0-incubating-SNAPSHOT to
1.4.0-incubating-SNAPSHOT. Since release/v1.3 has been cut from main, main
should now advance to the next version line.

Updated version references:

• build.sbt: ThisBuild / version → 1.4.0-incubating-SNAPSHOT
• bin/k8s/values.yaml: imageTag → 1.4.0-incubating-SNAPSHOT
• frontend/package.json: version → 1.4.0-incubating-SNAPSHOT

Any related issues, documentation, or discussions?

release/v1.3 is already at 1.3.0-incubating via #8306, so main now moves to
1.4.0-incubating-SNAPSHOT.

Closes #8305.

How was this PR tested?

Version-string-only change.

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: @Neilk1021, @kunwp1, @renovate-bot
  You can notify them by mentioning @Neilk1021, @kunwp1, @renovate-bot in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.07%. Comparing base (8aea604) to head (646883f).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8307   +/-   ##
=========================================
  Coverage     94.07%   94.07%           
  Complexity     4809     4809           
=========================================
  Files          1194     1194           
  Lines         48597    48597           
  Branches       5857     5857           
=========================================
+ Hits          45718    45719    +1     
  Misses         1428     1428           
+ Partials       1451     1450    -1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	81.00% <ø> (ø)
agent-service	99.32% <ø> (ø)		Carriedforward from 8aea604
amber	90.11% <ø> (+<0.01%)	⬆️
computing-unit-managing-service	73.67% <ø> (ø)
config-service	87.00% <ø> (ø)
file-service	87.91% <ø> (ø)
frontend	96.82% <ø> (ø)
notebook-migration-service	79.31% <ø> (ø)
pyamber	98.18% <ø> (ø)		Carriedforward from 8aea604
workflow-compiling-service	77.19% <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 · 🔴 2 worse · ⚪ 11 noise (<±5%) · 0 without baseline

Compared against main 8aea604 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	393	0.24	24,730/30,180/30,180 us	🟢 -13.7% / 🔴 +89.8%
🔴	bs=100 sw=10 sl=64	791	0.483	120,363/183,518/183,518 us	🔴 +27.8% / 🔴 +65.9%
⚪	bs=1000 sw=10 sl=64	937	0.572	1,060,104/1,142,824/1,142,824 us	⚪ within ±5% / 🔴 +8.4%

Baseline details

Latest main 8aea604 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	393 tuples/sec	410 tuples/sec	750.65 tuples/sec	-4.1%	-47.6%
bs=10 sw=10 sl=64	MB/s	0.24 MB/s	0.25 MB/s	0.458 MB/s	-4.0%	-47.6%
bs=10 sw=10 sl=64	p50	24,730 us	24,219 us	13,049 us	+2.1%	+89.5%
bs=10 sw=10 sl=64	p95	30,180 us	34,984 us	15,902 us	-13.7%	+89.8%
bs=10 sw=10 sl=64	p99	30,180 us	34,984 us	19,184 us	-13.7%	+57.3%
bs=100 sw=10 sl=64	throughput	791 tuples/sec	815 tuples/sec	960.3 tuples/sec	-2.9%	-17.6%
bs=100 sw=10 sl=64	MB/s	0.483 MB/s	0.497 MB/s	0.586 MB/s	-2.8%	-17.6%
bs=100 sw=10 sl=64	p50	120,363 us	119,536 us	104,199 us	+0.7%	+15.5%
bs=100 sw=10 sl=64	p95	183,518 us	143,625 us	110,645 us	+27.8%	+65.9%
bs=100 sw=10 sl=64	p99	183,518 us	143,625 us	120,888 us	+27.8%	+51.8%
bs=1000 sw=10 sl=64	throughput	937 tuples/sec	965 tuples/sec	993.27 tuples/sec	-2.9%	-5.7%
bs=1000 sw=10 sl=64	MB/s	0.572 MB/s	0.589 MB/s	0.606 MB/s	-2.9%	-5.6%
bs=1000 sw=10 sl=64	p50	1,060,104 us	1,038,904 us	1,012,191 us	+2.0%	+4.7%
bs=1000 sw=10 sl=64	p95	1,142,824 us	1,098,292 us	1,054,057 us	+4.1%	+8.4%
bs=1000 sw=10 sl=64	p99	1,142,824 us	1,098,292 us	1,081,313 us	+4.1%	+5.7%

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
0,10,10,64,20,509.43,200,128000,393,0.240,24730.21,30180.15,30180.15
1,100,10,64,20,2528.12,2000,1280000,791,0.483,120363.40,183517.75,183517.75
2,1000,10,64,20,21337.55,20000,12800000,937,0.572,1060103.76,1142823.60,1142823.60