feat: add integration tests (#6923)

### Summary

This PR introduces several integration tests, a mix of manually written
tests and those generated using the `generate-integration-tests` Python
script located in the `scripts` folder.

### Tests Added:
- **Authentication tests**: Validating login, registration, and token
handling.
- **FindMany queries**: Fetching multiple records for all existing
entities that do not require input arguments.

### How the Integration Tests Work:
- A `setupTest` function is called during the Jest test run. This
function initializes a test instance of the application and exposes it
on a dedicated port.
- Since tests are executed in isolated workers, they do not have direct
access to the in-memory app instance. Instead, the tests query the
application through the exposed port.
- A static accessToken is used, this one as a big expiration time so it
will never expire (365 years)
- The queries are executed, and the results are validated against
expected outcomes.

### Current State and Next Steps:
- These tests currently run using the existing development seed data. We
plan to introduce more comprehensive test data using `faker` to improve
coverage.
- At the moment, the only mutation tests implemented are for
authentication. Future updates should include broader mutation testing
for other entities.

---------

Co-authored-by: Charles Bochet <charles@twenty.com>

.vscode/twenty.code-workspace

@@ -20,6 +20,10 @@
       "name": "packages/twenty-ui",
       "path": "../packages/twenty-ui"
     },
+    {
+      "name": "packages/twenty-emails",
+      "path": "../packages/twenty-emails"
+    },
     {
       "name": "packages/twenty-postgres",
       "path": "../packages/twenty-postgres"