New keyboard shortcuts for review mode

The shortcuts

• J / K — next / previous applicant.
• 1–5 — assign a score on the current rubric criterion.
• Tab / Shift+Tab — next / previous rubric criterion within the applicant.
• ⌘↵ / Ctrl+↵ — advance the applicant to the next stage and move to the next applicant.
• N — open the notes panel without leaving the keyboard.
• ? — open the cheatsheet from anywhere.

Why it matters

Power reviewers were already living in the rubric. Letting them never touch the mouse cuts seconds per applicant, which adds up fast on a 600-applicant screening pass.