chore(ci): cache and parallelize web wasm builds

[404Wolf]

Web deploys currently compile cache-wasm, then agent-fold wasm, then Vite — sequentially, with no rustc cache. That rebuilds both wasm packages from scratch on every deploy.

Changes

Parallel. just build-dev / build-staging / build-prod now go through a [parallel] build-wasm recipe. Each wasm-pack crate gets its own CARGO_TARGET_DIR (target/cache-wasm, target/agent-fold-wasm) so the two release compiles do not serialize on the workspace cargo lock. Vite still waits for both.

Cache. Web build, preview, and deploy jobs now follow the existing typecheck pattern:

• Namespace web-ci remote sccache
• Cargo registry/git on the cache volume
• wasm-pack's downloaded wasm-opt cache (same path as the sync-service worker job)

CI still always rebuilds wasm (schema/engine changes can land without a version bump). The compiles just hit sccache instead of starting cold.

Path filters. Preview deploys and web PR checks now also run when crates/agent_fold or crates/agent_runtime_protocol change.

Tested

• just --dry-run build-dev emits both wasm-pack commands, then Vite
• cargo test -p xtask_workflows — 28 passed, including new coverage for the build/preview/deploy cache wiring
• cargo x workflows --check
• just check

Did not run a full wasm-pack + Vite production build in this environment.

  

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: 55555702-7137-490b-a119-891bfe422c21

📥 Commits

Reviewing files that changed from the base of the PR and between 6106355 and 6305106.

📒 Files selected for processing (14)

• .github/workflows/deploy_preview.yml
• .github/workflows/deploy_web_app.yml
• .github/workflows/web-app-check-main.yml
• apps/web/justfile
• tooling/xtask/crates/xtask_cache_wasm/src/main.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/deploy_preview.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/deploy_preview/test.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/deploy_web_app.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/deploy_web_app/test.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/steps.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/steps/test.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/web_app_check_main.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/web_app_check_main/test.rs
• tooling/xtask/crates/xtask_workflows/src/workflows/web_artifact_paths.rs

Included review availability: Your plan provides up to 8 included reviews per hour; 6 remain after this review.

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📝 Summary

Summary by CodeRabbit

• Performance

  • Improved web build performance by enabling parallel WebAssembly builds and expanded caching for Rust, Bun, and WebAssembly assets.
  • Added remote build-cache support with cache statistics and local fallback when unavailable.

• Builds & Deployments

  • Web checks and preview deployments now run when agent-related WebAssembly components change.
  • Web builds use a larger build environment for improved reliability.

• Testing

  • Added workflow validation to confirm caching, WebAssembly builds, and change detection behave as expected.

Walkthrough

The change adds parallel cache-WASM and fold-WASM build targets with separate Cargo output directories. Web workflows now cache Bun, Cargo, and wasm-pack data, configure shared Namespace sccache, and report statistics. Web build jobs use the web build cache and a larger runner where applicable. Changes to fold-WASM crates now trigger relevant workflows. Tests validate generated workflow configuration.

Priority: ➖ Normal

Merge Risk: ⚪ Minimal · up to 63051

No actionable merge-blocking risk is supported by the available evidence.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title uses the conventional commits format, clearly describes the caching and parallelization changes, and is 48 characters long.
Description check	✅ Passed	The description directly explains the parallel wasm builds, sccache and cache changes, path filters, tests, and known validation limits.

✨ Finishing Touches 💡 1

🛠️ Fix failing CI checks 💡

• Create stacked PR
• Commit on current branch

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