feat: UI overhaul - component library + route layouts with instant headers

- Created 11 reusable UI components: PageHeader, SectionCard, StatCard, StatusBadge, TabBar, MemberList, ActivityFeed, EventCard, ContentSkeleton, QuickLinkGrid, ModuleCard
- Created route-specific +layout.svelte for documents, calendar, kanban, events, settings, account
- Each layout renders PageHeader instantly from parent data, shows ContentSkeleton during navigation
- Removed full-page PageSkeleton from parent layout
- Refactored all pages to use new components instead of inline markup
- Overview page: uses StatCard, SectionCard, EventCard, ActivityFeed, MemberList, QuickLinkGrid
- Events list: uses EventCard, Button components
- Event detail: uses ModuleCard, SectionCard
- Settings/Account/Calendar/Kanban: headers in layouts, toolbars in pages
- Added i18n keys for overview page (EN + ET)
- 0 errors, 112 tests pass

messages/en.json

@@ -320,5 +320,11 @@
 	"events_mod_team": "Team",
 	"events_mod_team_desc": "Team members and shift scheduling",
 	"events_mod_sponsors": "Sponsors",
-	"events_mod_sponsors_desc": "Sponsors, partners, and deliverables"
+	"events_mod_sponsors_desc": "Sponsors, partners, and deliverables",
+	"overview_subtitle": "Welcome back. Here's what's happening.",
+	"overview_stat_events": "Events",
+	"overview_upcoming_events": "Upcoming Events",
+	"overview_upcoming_empty": "No upcoming events. Create one to get started.",
+	"overview_view_all_events": "View all events",
+	"overview_more_members": "+{count} more"
 }