US-008: Restructure DashboardLayout with SubNav, new tile order, and DetailPanel

- Wrap DashboardLayout with DetailPanelProvider in App.tsx
- Import and render DetailPanel component alongside CommandPalette
- Reorder tiles: PatientSummary (full) → LatestResults (half) + Projects (half) → CoreSkills (full) → LastConsultation (full) → CareerActivity (full) → Education (full)
- Update ProjectsTile from full-width to half-width (remove full prop)
- Update CoreSkillsTile from half-width to full-width (add full prop)
- SubNav already renders between TopBar and content
- Content area marginTop already accounts for both TopBar and SubNav heights
- All tiles already have data-tile-id attributes for SubNav scrolling

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

src/components/tiles/ProjectsTile.tsx

@@ -258,7 +258,7 @@ export function ProjectsTile() {
   )
 
   return (
-    <Card full tileId="projects">
+    <Card tileId="projects">
       <CardHeader dotColor="amber" title="ACTIVE PROJECTS" />
 
       <div style={{ display: 'flex', flexDirection: 'column', gap: '8px' }}>