QA: added unit test for api.ts

[Nubcoder0118]

No description provided.

[Nubcoder0118]

1. Install dependencies (from /frontend):

• npm install
• 2. Install test dependencies (if not already installed):
• npm install --save-dev jest ts-jest @types/jest
• 3. Run tests:
• npm test

• ---

• What these tests cover:

• ---

• • Correct API endpoint paths
• • Request methods (GET/POST)
• • Request body formatting
• • Authorization header injection
• • Error handling for failed requests

• ---

• Notes:

• ---

• • Uses mocked fetch and Supabase session
• • Safe to run without backend or Supabase
• • Designed for QA validation before integration
    */