fix(projects): fence file writers with a shared Project lock

[waleedlatif1]

Summary

Follow-up to #8609, which replaced the per-workspace folder lock on about 15 workspace-file write paths with lockWorkspaceProject: an exclusive advisory lock on the whole Project (a workspace and all its forks), with a 5s bound that becomes a 409 ProjectConflictError. Rename, delete, restore, image-dimension and chat-upload writes previously took no lock. Under #8609, every file write in every environment of a Project serialized, and contention surfaced as random 409s.

• File writers take the Project lock shared. They only need to be fenced against exclusive lifecycle holders: fork and split, archive, payer transfer, departure handoff, account deletion and retention. No workspace-file invariant needs writers to exclude each other: names use the per-workspace directory lock, storage uses the workspace row then the payer row, and revisions use file-row locks. The new lockWorkspaceProjectExclusive keeps today's semantics for fork, split and archiveWorkspace. I checked every caller, and no transaction upgrades from shared to exclusive.
• Bulk archive and folder restore lock the workspace row first. Their multi-row deleted_at updates upsert the search dispatch queue through the trigger, which deadlocked with a concurrent content write. The exclusive Project lock had been hiding that.
• Organization departure takes Project locks before the workspace-row owner update. Previously it locked workspace row then Project, the reverse of the file writers' Project then workspace row, which could deadlock with a file write in a fork Project.
• Payer transfer: zero-byte transfers skip the missing-destination check, Projects are locked once in order instead of one by one (and twice), and the test-only changeWorkspaceStoragePayersInTx entry point and its dead branch are removed. Tests now go through the real entry point.

Type of Change

• Bug fix

Testing

foundation.integration.ts: while one writer holds the shared Project lock, a writer in a sibling environment proceeds immediately (on the old code it hit the 5s timeout), and an exclusive lifecycle holder is still blocked. workspace-file-folder-manager.test.ts passes locally (12/12). Full suites in CI.

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 14, 2026 3:47pm UTC

[cubic-dev-ai]

All reported issues were addressed across 8 files

_{Turn on auto-fix | Re-trigger cubic}

[greptile-apps]

Confidence Score: 5/5

[High impact] The PR appears safe to merge; the latest change fixes the previously reported recursive-deletion deadlock.

Summary

File writers now share the Project lock while lifecycle operations keep exclusive locks.

• Workspace file writers share a Project lock while lifecycle changes stay exclusive.
• Bulk file changes lock the workspace row before changing file rows.
• Organization departure takes Project locks before changing workspace ownership.
• Payer transfers lock Projects together and route workspace moves through one path.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  W[File writer] --> S[Shared Project lock]
  S --> D[Directory lock when needed]
  D --> R[Workspace row lock]
  R --> F[File updates]
  L[Lifecycle operation] --> E[Exclusive Project lock]
  E -. waits for writers .-> S

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_{Reviews (2) · Last reviewed commit: "fix(files): lock the workspace row befor..." · Reviewed by Greptile}

[waleedlatif1]

@greptile

[waleedlatif1]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

@waleedlatif1 I have started the AI code review. It will take a few minutes to complete.

[cubic-dev-ai]

No issues found across 8 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

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