feat: apply KBX Foundation v4 pattern to home navigation

1. Create home feature registry (registry.ts)
   - Define homeScreen: KbxScreenDefinition
   - screenId: "home.dashboard"
   - Module: "Home"
   - Type: "dashboard"
   - Accessible to all users (no permissions required)

2. Update central registry (registry/screens.ts)
   - Import homeScreens from home/registry
   - Add homeScreens to getAllScreens()
   - Prepare for dynamic screen loading

3. Refactor HomePage.vue (KBX pattern)
   - Replace navigationCatalog with registry-driven screens
   - Use useKbxRegistry() composable
   - Dynamic module grouping from registry
   - Favorites/recent workbench
   - Attention items aggregation (DEBT-030)

4. Extend module types (kbx-types.ts)
   - Add "Home" to module union type
   - Support existing modules: Research, Operations, Portfolio, etc.
   - Flexible module extensibility

Features:
- Registry-driven navigation
- Centralized screen definitions
- Dynamic module grouping and sorting
- Favorites/recent screen tracking
- Type-safe screen lookups
- Zero hardcoded navigation paths

Benefits:
- Single source of truth for screen registry
- Automatic sync with router definitions
- Easy to add new modules
- Maintainable and testable

TypeScript: ✅ PASS (0 errors)
Typecheck time: ~5s

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/src/shared/contracts/kbx-types.ts

@@ -7,7 +7,7 @@
 export interface KbxScreenDefinition {
   screenId: string              // e.g., "model-ops.shadow-run.list"
   title: string                 // e.g., "Shadow Run Validation"
-  module: 'ModelOps' | 'SignalEngine' | 'Admin'
+  module: 'Home' | 'ModelOps' | 'SignalEngine' | 'Admin' | 'Research' | 'Operations' | 'Portfolio' | 'Design System' | 'Internal' | 'Other'
   type: 'list' | 'detail' | 'form' | 'dashboard'
   path: string                  // Vue Router path
   component: () => Promise<any> // Lazy-loaded component