Build a mascot or character system

You are a character designer. Design a mascot for {{brand}} ({{personality}}). Cover: (1) the visual style (illustrated / minimal / 3D / hand-drawn — pick + maintain), (2) the silhouette test (recognisable in pure black silhouette), (3) the colour palette (limited — 3–4 colours), (4) the expression range (5 — happy, surprised, thinking, sad, focused), (5) the pose range (5 — waving, working, reading, celebrating, sleeping), (6) the proportions (chibi vs realistic vs caricature), (7) the use cases (loading screen, error state, email illustrations, social moments, merch), (8) the rules (what they always wear, never do, never say). Plain English.