Profile username not extracted when network is already set (LinkedIn shows username: null)

[DDjohnson21]

Description

In transform_basics() (transform.py), a profile's username is only extracted from the URL when network is None. When extraction already provides a network (e.g. network: "LinkedIn"), the username extraction block is skipped entirely, so username stays null even though it's present in the URL.

Steps to reproduce

1. Use a resume with a LinkedIn URL, e.g. linkedin.com/in/damien-d-johnson.
2. Run the pipeline so the profile is parsed.
3. Inspect the resulting basics/profiles.

Actual

{ "network": "LinkedIn", "username": null, "url": "http://www.linkedin.com/in/damien-d-johnson" }

Expected

{ "network": "LinkedIn", "username": "damien-d-johnson", "url": "https://www.linkedin.com/in/damien-d-johnson" }

Impact

The empty username field is passed to the evaluator, where the LLM interprets the null as a problem and reports it under "areas for improvement" (e.g. "LinkedIn profile was marked 'None'"), even though the URL was found correctly.

Environment

• OS: macOS
• Python: 3.x
• Provider/model: Gemini (gemini-2.5-flash)