ci: extract shared setup prelude into composite action

[staging-devin-ai-integration]

Summary

• Extract the duplicated CI setup prelude (free-disk, checkout, bun/UI build, apt, rust toolchain, sccache, rust-cache) from all 5 skit.yml jobs into .github/actions/setup-skit/action.yml.
• The composite action accepts 5 inputs to handle per-job variations: rust-cache-key, rust-cache-workspaces, rust-components, skip-ui-build, runs-on-self-hosted.
• Each job now collapses to a single uses: ./.github/actions/setup-skit step plus its job-specific commands and (where applicable) sccache save.
• Bumping tool versions (Rust, Bun, action refs) now requires a single edit in the composite action.

Closes #436

Review & Validation

• Verify the composite action inputs cover all per-job variations: lint (rust-components: rustfmt, clippy), coverage (rust-cache-workspaces, rust-components: llvm-tools-preview), test-gpu (skip-ui-build, runs-on-self-hosted).
• CI passes on all 5 jobs — behavior should be identical to the previous inline steps.
• Spot-check that sccache cache keys remain compatible (pattern: sccache-{rust-cache-key}-{os}-{hash}).

Notes

• skip-ui-build is not set for lint because cargo clippy --workspace compiles skit, which embeds UI assets via RustEmbed. The issue suggested lint could skip UI build, but that would break clippy.
• Coverage previously used aggressive free-disk settings (large-packages: true, swap-storage: true); the composite uses the standard settings. If coverage hits disk-space issues, a free-disk-aggressive input can be added.
• Lint/test/build previously shared a single rust-cache key (skit); they now use per-job keys (skit-lint, skit-test, skit-build) to match the per-job sccache keys. First CI run after merge will have a one-time rust-cache miss.

Link to Devin session: https://staging.itsdev.in/sessions/90a735612c22449896cd1934b5d5d56e
Requested by: @streamer45

---

Devin Review

Status	Commit
🟢 Reviewed	6fa477b

[staging-devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[staging-devin-ai-integration]

Devin Review found 3 potential issues.

Debug

Playground

[staging-devin-ai-integration]

🔴 Local composite action is used before the repository is checked out

Each Skit job now starts with uses: ./.github/actions/setup-skit, but local actions are resolved from the runner workspace, which is empty until actions/checkout has already run. The checkout step was moved inside the local composite action (.github/actions/setup-skit/action.yml:44), so the runner cannot load that action in the first place and the lint/test/coverage/GPU/build jobs fail before any setup executes. The same first-step pattern appears at .github/workflows/skit.yml:50, .github/workflows/skit.yml:83, .github/workflows/skit.yml:131, and .github/workflows/skit.yml:167.

Prompt for agents

Fix the Skit reusable workflow so the repository is checked out before any local action is referenced. The new .github/actions/setup-skit composite action includes actions/checkout internally, but that cannot bootstrap loading the local action itself. Add an actions/checkout step before every uses: ./.github/actions/setup-skit invocation in .github/workflows/skit.yml, or replace the local action with a non-local reusable mechanism that does not require workspace files to already exist. If adding separate checkout steps, also consider removing the checkout step from .github/actions/setup-skit/action.yml to avoid checking out twice.

---

Was this helpful? React with 👍 or 👎 to provide feedback.

Debug

Playground

[staging-devin-ai-integration]

Already fixed in a35db2b — actions/checkout@v5 now runs before the composite action in every job, and the checkout step was removed from the composite action.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.38%. Comparing base (b2d01c2) to head (a35db2b).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #518      +/-   ##
==========================================
- Coverage   79.39%   79.38%   -0.02%     
==========================================
  Files         232      232              
  Lines       66904    66904              
  Branches     1909     1909              
==========================================
- Hits        53117    53110       -7     
- Misses      13781    13788       +7     
  Partials        6        6              

Flag	Coverage Δ
backend	79.10% <ø> (-0.02%)	⬇️
ui	82.06% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
core	85.27% <ø> (ø)
engine	83.59% <ø> (-0.10%)	⬇️
api	89.98% <ø> (ø)
nodes	75.31% <ø> (-0.02%)	⬇️
server	80.26% <ø> (ø)
plugin-native	83.47% <ø> (ø)
plugin-wasm	91.90% <ø> (ø)
ui-services	84.67% <ø> (ø)
ui-components	60.49% <ø> (ø)
see 2 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.