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>

shared/types/constraint.ts

@@ -0,0 +1,35 @@
+export type ConstraintType =
+  | 'max_hours_per_day'
+  | 'max_hours_per_week'
+  | 'min_rest_between_shifts'
+  | 'max_consecutive_shifts'
+  | 'max_consecutive_shift_type'
+  | 'min_consecutive_days_off'
+  | 'max_shifts_per_period_per_week'
+  | 'forbidden_shift_sequence'
+  | 'employee_unavailable'
+  | 'employee_prefers_period'
+  | 'employee_avoids_period'
+  | 'require_role_per_shift'
+  | 'max_weekend_shifts_per_month'
+  | 'fair_distribution'
+
+export type ConstraintScope =
+  | { type: 'global' }
+  | { type: 'employee'; employee_id: string }
+  | { type: 'role'; role: string }
+  | { type: 'period'; period_id: string }
+
+export interface ConstraintJSON {
+  type: ConstraintType
+  scope: ConstraintScope
+  params: Record<string, unknown>
+  hard: boolean
+  weight?: number
+  natural_language_summary: string
+}
+
+export interface ParsedConstraintResult {
+  constraints: ConstraintJSON[]
+  ambiguities: string[]
+}