[claude] Add an endpoint to request a CRDT snapshot rebuild

[myieye]

[Claude, autonomous]

POST /api/fw-lite/sync/request-crdt-snapshot-rebuild/{projectId} adds an empty commit dated before every other commit in the project. A client that receives a commit predating its history rolls its snapshots all the way back and replays everything, so each one rebuilds its snapshots the next time it syncs. Nothing is rebuilt server-side, and a client that never syncs never rebuilds. Admin only. An optional note goes into the commit metadata, and the response says how many commits clients will replay.

Tests cover what it promises: no commit sorts before the marker and it carries no changes, and a client with nothing left to sync is still sent it (which is what the fresh client id buys).

The mechanism was also checked outside the tests, by replaying a captured sync payload plus such a commit against a copy of a wedged production project's database: the resulting projected state came out byte-identical to a from-scratch rebuild.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Team

Run ID: 1fd8b446-5dfb-4c11-9416-573b602f3db3

📥 Commits

Reviewing files that changed from the base of the PR and between afcea01 and 063506b.

📒 Files selected for processing (3)

• backend/LexBoxApi/Controllers/SyncController.cs
• backend/LexBoxApi/Services/CrdtCommitService.cs
• backend/Testing/LexCore/Services/CrdtCommitServiceTests.cs

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

The service now creates empty CRDT snapshot-rebuild commits with replay metadata. An admin-only controller endpoint requests these commits. Tests cover commit ordering, replay counts, empty changes, and delivery to synchronized clients.

Changes

CRDT snapshot rebuild

Layer / File(s)	Summary
Snapshot-rebuild commit creation and validation backend/LexBoxApi/Services/CrdtCommitService.cs, backend/Testing/LexCore/Services/CrdtCommitServiceTests.cs	CrdtCommitService creates snapshot-rebuild commits and returns replay metadata. Tests validate commit ordering, empty changes, replay counts, and delivery to up-to-date clients.
Administrative rebuild endpoint backend/LexBoxApi/Controllers/SyncController.cs	SyncController injects CrdtCommitService and adds an admin-protected POST endpoint. The endpoint returns the created commit or 404 when the project has no CRDT commits.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 06350

This adds an admin-only request that causes syncing clients to replay project history from an empty marker commit. The marker behavior and delivery path are covered, with no remaining concrete merge-blocking risk.

Suggested reviewers: hahn-kev

Poem

A rabbit taps a rebuild bell
Empty commits march through the shell
Old histories wake and play
Admin paws now lead the way
Snapshots bloom before the day

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 44.44% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 9 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: adding an endpoint that requests a CRDT snapshot rebuild.
Description check	✅ Passed	The description accurately explains the new admin-only endpoint, marker commit behavior, optional note, replay count, client effects, and test coverage.
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.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch claude/force-crdt-snapshot-rebuild

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