Build batch dataset manifest workbench

[Andesha]

Brief summary of changes

• Add a manual batch workbench for reviewing recordings, assigning participants, and editing recording metadata.
• Add a batch manifest domain model with validation, readiness, participant-link propagation, and unit coverage.
• Add Vitest configuration and wire renderer unit tests into CI.
• Have you updated related documentation?

Testing instructions (if applicable)

1. Run npm run test:unit.
2. Run npm run lint.
3. Run npm run build.
4. Launch the application and open the batch workbench to review participant assignment and recording metadata editing.

Link(s) to related issue(s)

• Resolves Batch dataset import and manifest workbench #192

[Andesha]

Workflow direction update

The batch feature is converging well, but we are tightening the responsibility boundary before the remaining slices land.

The Batch workbench is a manifest authoring tool. Its only handoffs should be:

1. save a versioned batch manifest file; or
2. load that same serialized manifest directly into Configuration.

Configuration remains responsible for dataset-wide conversion settings. Recording to BIDS consumes the active manifest plus Configuration and remains responsible for destination preview, output preflight, conversion, per-recording results, and retry. The workbench should not grow a parallel configuration or conversion workflow.

The manifest is the canonical contract for both file loading and direct in-memory handoff. Configuration changes must not silently rewrite it, and global configuration values should not be duplicated into each recording row.

Issues #192, #197, #198, and #199 have been revised to reflect this direction. #199 now precedes #197 conceptually because save/load and direct handoff establish the contract consumed by the conversion workflow.

[Andesha]

Follow-up to the workflow pivot: the final workbench tab should remain, but as Review & handoff rather than Preview & Convert. Issue #199 now explicitly covers its manifest summary plus Save batch file and Load into Configuration actions. Output directory, modality, proposed BIDS destinations, and collision preflight remain outside the workbench under #197.