Workflows List Page

## Description

Create a new entity page for workflows accessible from the main navigation, displaying workflows as cards.

**Parent Epic:** #1144

## Acceptance Criteria

- [x] New `workflowsEntityConfig.ts` following existing entity patterns
- [x] "Workflows" link added to header navigation (gated by feature flag)
- [x] Page displays workflows as cards in a grid layout
- [x] Filters built dynamically from workflow.json data (Category, etc.)
- [x] Filter sidebar with search functionality
- [x] Page title: "Workflows"
- [x] Card component with:
- [x] Category label/tag displayed at top of card
- [x] Workflow name as card title
- [x] Truncated description with "Read more" link
- [x] "Configure" button that navigates to `/data/workflows/[workflowId]`

## Design Reference

Image 1 in Figma mocks:
- Prototype: https://www.figma.com/proto/wxBBIrZcZb6IhYSg4d8B7J/BRC-Analytics-Homepage?page-id=1%3A12&node-id=1382-3403&m=dev&scaling=min-zoom&content-scaling=fixed&starting-point-node-id=357%3A559&show-proto-sidebar=1
- Design: https://www.figma.com/design/wxBBIrZcZb6IhYSg4d8B7J/BRC-Analytics-Homepage?node-id=1382-3403&m=dev

## Technical Notes

- Follow pattern from `genomeEntityConfig.ts` and `organismEntityConfig.ts`
- Workflow data sourced from `/catalog/output/workflows.json`
- All functionality gated behind feature flag