data: expand LinkedIn MFE profiles to 693 (round 4)

Strategies: class-of-20XX, 18 top quant employers (Citadel,
Two Sigma, Jane Street, DE Shaw, etc.), department name
variations, broad MFE terms, low-count program targeting.

693 profiles (+148 new) across 15 programs:
CMU(89), Baruch(78), Berkeley(73), UChicago(57), Columbia(50),
GaTech(44), MIT(43), UCLA(43), NYU Tandon(39), Princeton(38),
NYU Courant(36), Cornell(35), Rutgers(30), UIUC(24), Stanford(14).

Data quality: 318+ employers, 122+ undergrad schools, 151+ grad years.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: YichengYang-Ethan