feat(project-files): add cross-owner copy and bulk transfers

[mzxchandra]

Summary

• Add independently authorized cross-owner copy, bounded ZIP extraction, recursive downloads, and Markdown snapshot export.
• Part 4 of feat(files): add the Project file backend and APIs #8610, rebased onto staging after refactor(files): unify mutation accounting and retention #9015–feat(project-files): add rendered delivery and indexed search #9017 merged. The diff contains only the copy/bulk slice and retains the parent fixes for rendering, provenance, search and retention.
• Keep Project public API/CLI documentation unpublished while preserving runtime contracts and commands. Restore the bulk-download and HEAD acceptance checks deferred from feat(project-files): add rendered delivery and indexed search #9017.

Validation

• 29 focused PostgreSQL content and authorization checks passed.
• 41 focused app unit tests and 32 CLI tests passed; scoped TypeScript check passed.
• 23 local app/relay HTTP and browser acceptance checks passed across delivery, rendered archives and cross-owner copy.
• Regenerated API/CLI metadata after synchronization. Hosted CI must validate the new head.

Stack

#9015–#9017 are merged. This PR targets staging; #9019 and #9034 remain downstream and need synchronization after this PR lands.

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Oct 15, 2026 1:36am UTC

[mzxchandra]

@greptile

[mzxchandra]

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[cubic-dev-ai]

All reported issues were addressed across 68 files

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[greptile-apps]

Confidence Score: 5/5

[High impact] The reviewed changes appear safe to merge.

Summary

Adds copies between workspace and Project owners, bounded ZIP extraction, recursive downloads, and Markdown snapshot export.

• Copied files get new identities in the destination owner.
• Project file selections download as ZIP archives.
• Markdown exports use the visible snapshot and its Project assets.
• Project ZIP files unpack into a new sibling folder.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Copy request] --> B[Check source read and destination write access]
  B --> C[Capture selected files and folders]
  C --> D[Stage copied bytes]
  D --> E[Recheck access and source selection]
  E --> F[Create destination tree and update storage usage]
  F --> G[Return new identities and notify destination]
  E -->|Rejected| H[Discard staged bytes]

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_{Reviews (4) · Last reviewed commit: "fix(files): recheck archive admission an..." · Reviewed by Greptile}

[mzxchandra]

@greptile

[mzxchandra]

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[cubic-dev-ai]

All reported issues were addressed

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[mzxchandra]

@greptile

[mzxchandra]

@cubic-dev-ai review this PR

[cubic-dev-ai]

@cubic-dev-ai review this PR

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

[cubic-dev-ai]

All reported issues were addressed across 69 files

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[mzxchandra]

Post-deploy staging verification (October 14, Pacific), with Projects disabled: verified traffic cutover and serving image for e111f4f before testing.

PASS: workspace bulk ZIP source bytes/filenames, nested paths, ZIP delivery headers, authorized bodyless HEAD, unauthenticated GET/HEAD denial, unknown/mixed folder-path rejection, and unchanged original source hashes/metadata. Temporary synthetic subtree cleaned up; original fixtures preserved.

Workspace-to-workspace copy also requires Projects and correctly returned the disabled-feature response. Successful copy/reference rewriting and Project archive/snapshot/extraction are NOT RUN. Restricted-role policy checks, internal-session folder-ID/browser flows, and production are not covered. No flags or roles changed.