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/3-solutioning/check-implementation-readiness/steps/step-06-final-assessment.md

@@ -6,7 +6,7 @@ description: 'Compile final assessment and polish the readiness report'
 workflow_path: '{project-root}/_bmad/bmm/workflows/3-solutioning/implementation-readiness'
 
 # File References
-thisStepFile: '{workflow_path}/steps/step-06-final-assessment.md'
+thisStepFile: './step-06-final-assessment.md'
 workflowFile: '{workflow_path}/workflow.md'
 outputFile: '{planning_artifacts}/implementation-readiness-report-{{date}}.md'
 ---