fix: unify theme system - fix theme switching persistence

- Unified localStorage key to 'theme-preference' across all components
- Fixed header.tsx using wrong localStorage key ('theme' instead of 'theme-preference')
- Added localStorage hybrid persistence for instant theme changes
- Removed router.refresh() which was causing stale data revert
- Replaced Blue theme with Sepia
- Consolidated auth() calls to prevent race conditions
- Updated UserSettingsData types to include all themes

_bmad/bmm/workflows/testarch/test-design/instructions.md

@@ -25,11 +25,11 @@ The workflow auto-detects which mode to use based on project phase.
 ### Mode Detection
 
 1. **Check for sprint-status.yaml**
-   - If `{output_folder}/bmm-sprint-status.yaml` exists → **Epic-Level Mode** (Phase 4)
+   - If `{implementation_artifacts}/sprint-status.yaml` exists → **Epic-Level Mode** (Phase 4)
    - If NOT exists → Check workflow status
 
 2. **Check workflow-status.yaml**
-   - Read `{output_folder}/bmm-workflow-status.yaml`
+   - Read `{planning_artifacts}/bmm-workflow-status.yaml`
    - If `implementation-readiness: required` or `implementation-readiness: recommended` → **System-Level Mode** (Phase 3)
    - Otherwise → **Epic-Level Mode** (Phase 4 without sprint status yet)