Fix integration test coverage upload to Codecov (#426)

## Problem

The integration-tests flag in `codecov.yml` was incorrectly configured
to look for coverage in `tests/**` paths, but Jest collects coverage
from `src/**` files (as specified in `jest.config.js`). This caused
integration test coverage to not be properly tracked by Codecov.

## Root Cause

- Jest's `collectCoverageFrom` config specifies `src/**` 
- Integration tests in `tests/**` exercise application code in `src/**`
- Test files (`**/*.test.ts`) are explicitly ignored in codecov config
- The mismatch meant coverage data wasn't associated with the
`integration-tests` flag

## Solution

Updated the `integration-tests` flag to cover `src/**` paths, matching
the actual coverage data generated by Jest.

Both unit tests and integration tests now correctly point to `src/**`
since both generate coverage for source code, just through different
test suites.

## Testing

This PR will verify that integration test coverage is properly uploaded
to Codecov when CI runs.

Author: ammar-agent

codecov.yml

@@ -33,7 +33,7 @@ flags:
     carryforward: false
   integration-tests:
     paths:
-      - tests/**
+      - src/**
     carryforward: false
 
 # Ignore common non-source paths