Initial commit: TKB Timeshift Schedule Management Application

- Next.js 15.2.4 with React 19 and TypeScript
- Monthly schedule generator with Excel-like formatting
- Complete employee list from example.xlsx (18 employees)
- Excel-style column naming (A, B, C, ..., Z, AA, AB, ...)
- Counter-clockwise text rotation for data values
- Weekend highlighting and shift color coding
- Team selection for TKB, METRO, D8
- 7 days from previous month + full current month date range
- jspreadsheet integration for Excel-like interface

🤖 Generated with [Claude Code](https://claude.ai/code)

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

v0_extracted/components/ui/collapsible.tsx

@@ -0,0 +1,11 @@
+"use client"
+
+import * as CollapsiblePrimitive from "@radix-ui/react-collapsible"
+
+const Collapsible = CollapsiblePrimitive.Root
+
+const CollapsibleTrigger = CollapsiblePrimitive.CollapsibleTrigger
+
+const CollapsibleContent = CollapsiblePrimitive.CollapsibleContent
+
+export { Collapsible, CollapsibleTrigger, CollapsibleContent }