fix(test): dedupe and serialize chunked batch-rerun dispatch

[crypticsaiyan]

Summary

Previously, running test rerun --all would split requests into chunks of 50 tests and dispatch all chunks concurrently using Promise.all. However, the backend's producer/teardown deduplication logic operates within a single request, not across concurrent requests. If two tests in different chunks shared a project's producer or teardown, the backend would independently decide "not yet triggered" for both, causing the shared dependency to execute multiple times.

Note: This concurrent dispatch bug applied to both the initial batch dispatch and the deferred-retry loop.

The Fix

Implemented sequential chunk dispatch and a client-side deduplication defense layer to prevent double-execution:

• Sequential Dispatch: Replaced Promise.all with sequential execution (one await per chunk). By the time chunk N is sent, chunk N-1 has already landed server-side, allowing the backend to correctly deduplicate shared dependencies against the previous chunk.
• Client-Side Defense: Added dedupeBatchRerunAccepted to drop duplicate testId entries from the aggregated accepted list, and mergeBatchRerunClosureByProject to safely merge closure.byProject entries without double-counting. The CLI now emits a warning to stderr if it detects and filters out a duplicate trigger.
• Fixture Update: Fixed a pre-existing test fixture (D3: batch rerun summary...) that was artificially relying on the old double-counting bug.

Testing & Validation

Regression Test: Added new test cases in src/commands/test.rerun.spec.ts to verify serialization and deduplication.

• Concurrency limit: Simulated timed mock responses to prove that chunks are strictly dispatched sequentially (concurrency never exceeds 1).
• Client deduplication: Simulated a backend incorrectly accepting a shared producer across two chunks to assert that the CLI successfully deduplicates the entry and emits a stderr warning.

CI Gates: All local checks pass.

• npm run lint & npm run format:check
• npm run typecheck
• npm test (1449 tests passing)
• npm run test:coverage (≥80% threshold met; actual ~87%)

Files Changed:

• src/commands/test.ts
• src/commands/test.rerun.spec.ts