feat: Add embeddable FHIR scheduler widget with slot hold system

[horner]

Summary

Adds an embeddable React scheduling widget (@mieweb/fhir-scheduler) that can be dropped into any application to provide appointment booking functionality against a FHIR-compliant server.

New Features

🗓️ Embeddable Scheduler Widget

• Provider List - Browse and select from available providers
• Slot Calendar - View available dates with slot counts, select time slots
• Booking Form - Capture patient info with hold countdown timer
• Confirmation - Display booking success/failure

🔒 Slot Hold API (prevents double-booking)

Method	Endpoint	Description
POST	/Slot/:id/$hold	Acquire temporary hold
GET	/Slot/:id/$hold	Check hold status
DELETE	/Slot/:id/$hold/:token	Release hold

🧪 Test Infrastructure

• Playwright E2E test scaffolding (7 test cases)
• Auto-starts both servers during test runs

📊 Data Generation

• Extended from 30 → 180 days of test data
• 50% fill rate (was 75%) for realistic availability

Usage

import { SchedulerWidget } from '@mieweb/fhir-scheduler';

<SchedulerWidget
  fhirBaseUrl="http://localhost:4010"
  onComplete={(appointment) => console.log('Booked:', appointment)}
/>

Demo

Run both servers and visit http://localhost:5174:

npm run dev                    # Backend on :4010
cd packages/fhir-scheduler && npm run dev  # Widget on :5174

Checklist

• Slot hold system implemented
• All phases 1-3 complete
• Playwright test scaffolding added
• QuestionnaireRenderer integration (placeholder)
• Comprehensive test coverage
• npm publish

[horner]

📸 *Documentation screenshots addedpush

See the full README with screenshots: https://github.com/mieweb/FHIRTogether/blob/embed-sched-component/packages/fhir-scheduler/README.md

Screenshots show the complete booking flow:

• Provider selection
• Date/calendar views
• Time slot selection
• Booking form with hold timer
• Confirmation
• Mobile responsive views