fix(flask): raise exception when cart is empty

[seer-by-sentry]

Fixes REACT-59F. The issue was that: Flask backend's checkout function uses quantities before definition, causing NameError and generic 500 response, leading to frontend response.status being undefined.

• Raise an exception when the cart is empty during checkout to prevent errors.

This fix was generated by Seer in Sentry, triggered by [email protected]. 👁️ Run ID: 1494963

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Project	Deployment	Preview	Comments	Updated (UTC)
empower	Ignored	Preview		Sep 18, 2025 5:52pm

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: flask/src/main.py

Function	Unhandled Issue
checkout	Exception: Error validating enough inventory for product ... Event Count: 110k
checkout	DatabaseConnectionError: get_inventory checkout Event Count: 136

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 25.74%. Comparing base (80b2c23) to head (56cabd9).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
flask/src/main.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1034   +/-   ##
=======================================
  Coverage   25.74%   25.74%           
=======================================
  Files          41       41           
  Lines        1134     1134           
  Branches      128      128           
=======================================
  Hits          292      292           
  Misses        819      819           
  Partials       23       23           

Flag	Coverage Δ
api	6.00% <0.00%> (ø)
frontend	42.23% <ø> (ø)

Components	Coverage Δ
checkout_module	6.00% <0.00%> (ø)
product_component	39.15% <ø> (ø)

Files with missing lines	Coverage Δ
flask/src/main.py	0.00% <0.00%> (ø)