fix(sandbox): make publish()'s untracked-dir stat check async

[pedrofrxncx]

Follows #5497 and #5481, which converted this same file's hooks-dir creation and decofile-block validation read from sync fs to async — one more sync-fs spot in packages/sandbox/daemon/routes/git.ts remained.

expandUntrackedDirs() (called from publish(), the daemon's git-publish route) used fs.statSync per changed path to detect an untracked directory that git status --porcelain collapsed into a single entry. Per CONTRIBUTING.md rule #1, any sync fs call in packages/sandbox/daemon/** blocks the daemon's single-threaded Bun event loop for its duration, which can make it miss its health probe — Studio then marks the sandbox dead and tears it down/triggers recovery on a single miss.

Why a maintainer wants this: publish() runs on every interactive publish and on shutdown sync, so this blocking call executes on a routine, frequently-hit path, not an edge case.

Change: expandUntrackedDirs is now async and uses stat from node:fs/promises instead of fs.statSync; its one call site in publish() now awaits it. No behavior change — same directory-detection logic, just non-blocking.

How to confirm: bun test packages/sandbox/daemon/routes/git.test.ts (51 tests, all passing, including the publish() coverage for untracked .deco/ directory expansion).

Locally ran: bun run fmt, bunx tsc --noEmit (packages/sandbox), the targeted test file above, and bunx oxlint packages/sandbox/daemon/routes/git.ts (0 warnings/errors). Full CI validates the rest.

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Summary by cubic

Make the untracked-dir stat check in the git publish route async to keep the daemon responsive. In packages/sandbox/daemon/routes/git.ts, expandUntrackedDirs now uses stat from node:fs/promises and publish() awaits it; no behavior change.

• Bug Fixes
  • Eliminates a sync FS hotspot on the frequent publish/shutdown path, preventing Bun event loop blocking and reducing sandbox health probe misses.

^{Written for commit f5e81b8. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 1 file

_{Re-trigger cubic}