Add careers link to README and startup log

[robinjhuang]

Adds a small link to comfy.org/careers in the README and a one-line note in the server startup output.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds hiring promotion across two surfaces. The README gains a hiring callout in the "Support and dev channel" section, directing readers to the careers page. The server startup now logs the same hiring message when running in verbose mode, appearing alongside the initial "Starting server" output. Both additions reference comfy.org/careers.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main changes: adding a careers link to both the README and server startup log.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description check	✅ Passed	The PR description clearly relates to the changeset, describing the addition of a careers link to the README and server startup log.

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