Replace mock data with real fetchTasks() API call. Add workspace-aware
data fetching, MosaicSpinner loading state, empty state card, and
error state with retry using design tokens throughout.
Refs #467
- Update WorkspaceGuard to support query string as fallback (backward compatibility)
- Priority order: Header > Param > Body > Query
- Update web client to send workspace ID via X-Workspace-Id header (recommended)
- Extend apiRequest helpers to accept workspace ID option
- Update fetchTasks to use header instead of query parameter
- Add comprehensive tests for all workspace ID transmission methods
- Tests passing: API 11 tests, Web 6 new tests (total 494)
This ensures consistent workspace ID handling with proper multi-tenant isolation
while maintaining backward compatibility with existing query string approaches.
Fixes#194
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
