Create yehyunchoi.md (#2555)

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Quote project_title since it has a ":" in the title

* style: pre-commit fixes

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Co-authored-by: Rob Tuck <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

_fellows/2025/yehyunchoi.md

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+---
+layout: fellow
+pagetype: fellow
+shortname: dbizdfvy
+permalink: /fellows/dbizdfvy.html
+fellow-name: Yehyun Choi
+title: Yehyun Choi - IRIS-HEP Fellow
+active: True
+dates:
+  start: 2025-06-01
+  end: 2025-08-23
+photo: /assets/images/team/fellows-2025/Yehyun-Choi.JPG
+institution: Cornell University
+e-mail: yc2698@cornell.edu
+focus-area: AS
+challenge-area:
+project_title: "Split Uproot into two phases: metadata-reading and data-reading"
+project_goal: >
+    This project aims to modularize Uproot and improve its performance, splitting the metadata-reading phase and the data-reading phase.
+mentors:
+  - Andres Rios-Tascon (Princeton University)
+  - Nick Smith (Fermilab)
+  - Ianna Osbonre (Princeton University)
+proposal: /assets/pdf/fellows-2025/Proposal-Yehyun-Choi.pdf
+presentations:
+  - title:
+    date:
+    url:
+    meeting:
+    meetingurl:
+    recordingurl:
+    focus-area:
+current_status: >
+  A placeholder for status updates
+github-username: dbizdfvy
+---