feat: complete ShiftCraft — AI-powered shift scheduling SaaS

Complete implementation including:
- Landing page with hero, features, how-it-works, pricing
- Employee management (CRUD with soft delete)
- AI constraint parser (Anthropic Claude API)
- German labor law templates (ArbZG §3, §5, §9)
- HiGHS ILP solver for optimal fair schedules
- Schedule calendar result view (employee × date grid)
- Shift framework configuration (periods + shifts)
- Subscription tiers: Free / Pro / Business
- PocketBase setup script with collection creation + seed data
- .env.example with all required variables documented

Pages: employees, constraints (list/new/templates), schedules (list/new/[id]),
       settings (organization/shifts/billing), dashboard

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

server/utils/solver/feasibilityCheck.ts

@@ -0,0 +1,32 @@
+import type { SolveInput } from '~/shared/types/schedule'
+
+interface FeasibilityIssue {
+  message: string
+  blocking: boolean
+}
+
+export function checkFeasibility(input: SolveInput): FeasibilityIssue[] {
+  const issues: FeasibilityIssue[] = []
+  const { employees, framework } = input
+
+  if (employees.length === 0) {
+    issues.push({ message: 'Keine Mitarbeiter vorhanden', blocking: true })
+    return issues
+  }
+
+  if (framework.shifts.length === 0) {
+    issues.push({ message: 'Keine Schichten definiert', blocking: true })
+    return issues
+  }
+
+  // Check if enough employees for the highest shift requirement
+  const maxRequired = Math.max(...framework.shifts.map(s => s.workers_required))
+  if (employees.length < maxRequired) {
+    issues.push({
+      message: `Zu wenige Mitarbeiter: ${maxRequired} benötigt, nur ${employees.length} vorhanden`,
+      blocking: true
+    })
+  }
+
+  return issues
+}