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

.claude/commands/bmad/bmm/workflows/prd.md

@@ -0,0 +1,5 @@
+---
+description: 'PRD tri-modal workflow - Create, Validate, or Edit comprehensive PRDs'
+---
+
+IT IS CRITICAL THAT YOU FOLLOW THIS COMMAND: LOAD the FULL @_bmad/bmm/workflows/2-plan-workflows/prd/workflow.md, READ its entire contents and follow its directions exactly!

.claude/commands/bmad/bmm/workflows/quick-spec.md

@@ -0,0 +1,5 @@
+---
+description: 'Conversational spec engineering - ask questions, investigate code, produce implementation-ready tech-spec.'
+---
+
+IT IS CRITICAL THAT YOU FOLLOW THIS COMMAND: LOAD the FULL @_bmad/bmm/workflows/bmad-quick-flow/quick-spec/workflow.md, READ its entire contents and follow its directions exactly!