Implement Stripe checkout/payment workflow stabilization and improve the ShoeInn booking experience to support a more production-ready customer payment flow.

[mrwrite]

Overview

This PR focuses on stabilizing and improving the ShoeInn booking and payment workflow to better support live demos and real-world booking scenarios.

The updates primarily address issues around Stripe checkout redirects, booking/payment flow reliability, and improving the overall customer checkout experience to feel more similar to modern delivery/service apps like DoorDash and Uber Eats.

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Key Changes

Stripe Checkout & Redirect Fixes

• Fixed Stripe redirect/payment flow issues causing failed or invalid checkout redirects.
• Corrected checkout success/cancel URL handling.
• Improved backend handling for PAYMENT_MODE=service Stripe checkout sessions.
• Resolved HTTP 502 booking/payment failures caused by invalid or placeholder redirect URLs.
• Improved validation and handling around Stripe session creation.

Booking & Payment Workflow Improvements

• Refined booking confirmation/payment experience to better mirror modern delivery app UX patterns.
• Added support for displaying a payment summary during the booking confirmation flow.
• Improved booking flow structure so users can:
  • Review service details
  • Review pricing/charges
  • Select payment method
  • Confirm booking before redirecting to Stripe

API & Environment Updates

• Updated backend configuration handling for Stripe-related environment variables.
• Improved local development startup reliability for the FastAPI/Uvicorn API.
• Added/fixed environment setup requirements for mobile/frontend integration.

Mobile & Frontend Enhancements

• Continued integration work between mobile booking screens and Stripe checkout flow.
• Improved booking confirmation UI handling after payment link execution.
• Added groundwork for a more polished customer checkout experience.

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Testing Performed

Backend

• Verified FastAPI application starts successfully with Stripe configuration enabled.
• Verified checkout session generation succeeds without HTTP 502 errors.
• Verified success/cancel redirect URLs are generated correctly.

Frontend / Mobile

• Tested booking flow through service selection and payment confirmation.
• Tested Stripe payment link redirect behavior.
• Verified customer can reach checkout flow successfully from the mobile app.

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Notes

• This PR is part of the ongoing effort to make ShoeInn fully demo-ready for live presentations with potential cleaning providers.
• Additional upcoming work will include:
  • Full payment summary UI polish
  • Expanded payment method support
  • Improved provider/customer booking state synchronization
  • Additional production hardening and UX refinement