iOS Safari auto-zooms (and shifts the viewport right) on focus when the
computed font-size is <16px. Single @media (max-width: 767px) block in
globals.css covers all four input tiers, every relevant bare <input>
type, <textarea>, <select>, and contenteditable surfaces. `!important`
is required because Tailwind utilities (text-[15px] on the chat composer,
text-sm on form fields) emit after @layer components and would otherwise
override the input-tier rules.
Replaces ad-hoc per-input `text-base md:text-sm` overrides with a single
global truth. New inputs/contenteditables get the fix for free.
Spec: docs/systems/design-system.md gains an "iOS Auto-Zoom Suppression"
section under Input Tiers.
Jannis Braun
f733e39b4a