Summary

Change actions/cache path from node_modules/.cache/turbo (turbo v1 default) to .turbo/cache (turbo v2 default) so the cache dir actually has contents to save, and add a per-job discriminator (-typecheck / -unit) to the cache key so the two concurrent jobs stop racing on the same reservation.

Why

ci / unit spends ~232s on every PR, even YAML-only ones. Root cause is a two-layer cache failure that compounds: the cache path pointed at an empty directory (turbo v1 default, but we run turbo v2), so every post-step logged [warning]Path Validation Error: Path(s) specified in the action for caching do(es) not exist, hence no cache is being saved. — no turbo-Linux-* entry ever landed in the pool (verified: 37 caches, 10.3 GB, zero turbo entries). Even with the path fixed, both jobs shared the exact same cache key, so they would race on reserveCache; per actions/toolkit source, the loser catches ReserveCacheError and logs it at info level without uploading. typecheck (~60s) always finishes before unit (~232s), so unit's cache would never enter the pool and subsequent runs would restore typecheck-flavored tarballs into unit jobs, producing task-hash misses and another full 232s run. Splitting the keys makes each job own its own slice.

Related Issue

Closes #74. The issue lists three levers: turbo cache fix (this PR), --filter=...[origin/dev] (obsoleted by turbo's own content-hash skipping once cache is working), and bun / desktop-electron concurrency (independent micro-optimisation, open a fresh issue if benchmark warrants it). Note: the issue body's passThroughEnv: ["*"] hypothesis is not the root cause — local turbo --dry=json with fake GitHub runner env produces identical task hashes, confirming passThroughEnv is a "pass through but don't hash" allowlist, not the opposite.

How To Verify

Pre-merge (local, already run):

bun turbo run test:ci --filter=opencode --dry=json 2>/dev/null \
  | jq '.tasks[] | {hash, envMode, passThroughEnv}' > /tmp/h1.json
GITHUB_RUN_ID=9999 GITHUB_SHA=deadbeef bun turbo run test:ci --filter=opencode --dry=json 2>/dev/null \
  | jq '.tasks[] | {hash, envMode, passThroughEnv}' > /tmp/h2.json
diff /tmp/h1.json /tmp/h2.json   # empty diff confirms env does not affect hash

Post-merge (CI observation — cannot be reproduced locally because actions/cache save/restore only runs on GitHub runners):

• On this PR's own ci / unit and ci / typecheck runs: post-step should log Cache saved with key: turbo-Linux-typecheck-... and turbo-Linux-unit-... (no Path Validation Error, no ReserveCacheError).
• On the next non-docs-only PR after merge: both jobs log Cache restored from key: turbo-Linux-typecheck-... / turbo-Linux-unit-...; bun turbo test:ci output contains >>> FULL TURBO for unchanged tasks.
• Cache pool check: gh api /repos/Astro-Han/pawwork/actions/caches | jq '.actions_caches[].key' | grep turbo should return turbo-Linux-typecheck-* and turbo-Linux-unit-* entries.

Checklist

• I ran the relevant verification steps
• I tested visible changes manually when needed (N/A — CI-only change)
• I am targeting the dev branch

Summary by CodeRabbit

No user-visible changes

This release contains only internal infrastructure updates to the continuous integration build pipeline. No new features, bug fixes, or user-facing functionality have been modified.