Add Ziqian Zhu to CONTRIBUTORS.md

[ziqianz360]

Objective and plan

Closes #44 and Relates to #5

Change

Evidence

Research interpretation

Contribution credit

Review

• The issue's acceptance criteria are addressed, or remaining work is explicitly linked.
• Evidence and contribution credit are accurate and reviewable.
• Changes to scope, methods, or decisions are reflected in the canonical plan/log when applicable.

[zhongnz]

Maintainer review (tool-assisted) of b63d9bdc54f1952142615d3f011d28e8460ff110: the net change is one alphabetically placed roster row for Ziqian Zhu / @ziqianz360, with a matching HTTPS GitHub profile link. The original student commit b777aa483b88e65e19e582d79e500954b6989a34 remains in history; maintainer integration only handles the current base, roster order and link formatting.

The linked task is an onboarding contribution under #5, with no separate research grade. No experiment, grading, permission or workflow settings changed. Required CI must pass on this revision before the normal protected-branch merge. Only this student's onboarding task should close; #5 stays open for the cohort.