ci(rust): skip unnecessary setup steps

[Standing-Man]

Rationale

Rust CI was doing redundant work in two areas:

1. Lightweight checks such as formatting, dependency sorting, and
   cargo machete installed nextest and system dependencies that they
   did not use.

This increased both CI setup time and total compute usage.

What changed?

• Added configurable Rust setup options for installing nextest and
  platform-specific system dependencies.
• Skipped unnecessary setup for formatting, sorting, and machete jobs.
• Explicitly enabled nextest only for jobs that require it.

Results

The setup optimization was measured over three runs:

Measurement	Baseline median	Optimized median	Improvement
Rust setup step	44 s	13 s	31 s / 70.5%
Benchmark job	52 s	20 s	32 s / 61.5%

A pre-merge comparison showed:

Job	Baseline	Optimized	Improvement
fmt	47 s	22 s	25 s / 53%
sort	42 s	19 s	23 s / 55%
machete	79 s	61 s	18 s / 23%
Combined	168 s	102 s	66 s / 39%

The benchmark link.

Local Execution

• Passed / not passed
  Passed
• Pre-commit hooks ran / not ran
  Ran

AI Usage

[github-actions]

Thanks for the PR. It is labeled S-waiting-on-review and queued for review.

Slash commands (own line, regular comment) move it around the queue:

• /ready - back to S-waiting-on-review after addressing feedback
• /author - flip to S-waiting-on-author while you finish changes
• /request-review @user-or-team - request a reviewer

See CONTRIBUTING.md for details.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.80%. Comparing base (ddead57) to head (321150f).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3749      +/-   ##
============================================
- Coverage     75.86%   75.80%   -0.07%     
  Complexity      969      969              
============================================
  Files          1323     1323              
  Lines        160111   160111              
  Branches     133501   133576      +75     
============================================
- Hits         121476   121376     -100     
- Misses        34993    35005      +12     
- Partials       3642     3730      +88     

Components	Coverage Δ
Rust Core	75.75% <ø> (-0.03%)	⬇️
Java SDK	62.71% <ø> (ø)
C# SDK	71.16% <ø> (-1.11%)	⬇️
Python SDK	93.10% <ø> (ø)
PHP SDK	84.52% <ø> (ø)
Node SDK	96.30% <ø> (+0.08%)	⬆️
Go SDK	43.08% <ø> (ø)
see 51 files with indirect coverage changes

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[slbotbm]

The cpp bdd failure looks like a transient network failure

[hubcio]

very nice! i'll review this today

[hubcio]

the direction here is good, and the PR closes a real pre-existing hole worth naming: previously test-1 and test-2 each ran their own git fetch origin master and cargo rail plan, so two racing fetches could resolve different origin/master, produce different -E filters, and let a test fall out of both partitions. one build shipping a single nextest-filter.txt makes the partitions complementary by construction.

one blocker, on the artifact name - see the comment at line 323 of the composite action. everything else is should-fix or polish.

one finding lands outside the diff so it has no line to attach to: Install cargo-nextest in setup-rust-with-cache still carries continue-on-error: true, but this PR deletes the cargo test fallback that made a missing nextest survivable. a curl flake now shows a green setup step and dies several steps later at cargo nextest archive with "no such command: nextest". the flag has outlived its reason - worth dropping while you're in there.

[Standing-Man]

/ready

[hubcio]

@Standing-Man something is still wrong:

it's building *-rust-tests tasks for all SDKs. it doesnt look good.

/author

[hubcio]

overall i'm happy with the speedup itself, but i still don't like this skipped jobs noise:

@Standing-Man could you please think of restructuring the code so that we would cut this noise? can be done in in next PR / future.

[hubcio]

I took a peek at CI logs. why are we uploading something to codecov in job build-rust-tests? the tests itself were not yet executed.

https://github.com/apache/iggy/actions/runs/30797637786/job/91636081622?pr=3749

[hubcio]