Ship LaunchPad audit fixes: all-advisor chat, knowledge seed, quieter gate.

Harden OpenAI key handling and stop echoing keys in chat errors.

Fix guest sign-in failing on invalid .local email.

Add LinkedIn and About Me expansion support for advisors.

Add guest try-mode and internship vs full-time path gate.

Improve LaunchPadAI quality: career canvas, personas, onboarding.

Add LaunchPadAI undergraduate internship advisor panel.