feat(textarea): add Textarea atom (no variants, sm/md/lg, aria-invalid)

[dgraciac]

Summary

Adds the Textarea atom — multi-line text input that completes the form-control sibling pair started by Input (0.6.0). Same chrome (border tone, focus ring, inline padding per size, aria-invalid error state), same composition philosophy (Escuela 1 / D11: no error / helperText / icon-slot props on the atom; the consumer composes <label>, helper, and error message — the future <Field> molecule will encapsulate that pattern).

• Three size values (sm / md / lg). Inline padding and font-size per size are identical to Input's, so a <Textarea> lines up flush with <Input> controls in the same form.
• Vertical dimension uses min-height (~3-4 lines at the size's font-size) instead of a fixed height. resize: vertical lets the user drag the bottom edge to grow it; consumers can override via style.resize if needed.
• Error state via aria-invalid="true" (CSS reacts to the attribute selector), matching shadcn / Base UI / Mantine and the Input atom.
• No useRender polymorphism — <textarea> has no meaningful render-as use-case, same reasoning as Input.
• Resting border --pharos-color-neutral-500 (~5.4:1 vs white) — same WCAG 1.4.11 fix that landed for Input / Button-secondary / Badge-outline in 0.6.0.

API

import { Textarea } from '@code-sherpas/pharos-react';

<Textarea size="md" placeholder="Tell us…" />
<Textarea aria-invalid="true" defaultValue="Too short." />
<Textarea disabled defaultValue="Read-only-ish" />
<Textarea rows={5} />            // native attr passthrough
<Textarea ref={textareaRef} />   // ref forwarded to <textarea>

TextareaProps extends ComponentProps<'textarea'> plus the typed size axis. No native attribute is shadowed (unlike Input, which reuses the size slot — <textarea> has no native size attribute).

Storybook

Components/Textarea: Playground, Default, Disabled, ReadOnly, Invalid (aria-invalid), WithLabel (composition pattern), Matrix (sizes × states grid).

Test plan

• pnpm typecheck — clean.
• pnpm lint — clean.
• pnpm format:check — clean.
• pnpm build — Vite library build + verify:dist-types smoke pass.
• pnpm test — 79 tests across 6 files, 0 failures (10 new Textarea tests).
• Chromatic baseline — published by CI on push; manual approval required for the new Textarea story snapshots.
• CI checks on PR.

Out of scope

• Adoption in alexandria-web-application — separate PR, opens after this one publishes (0.8.0) and after currently open Alexandria PRs are settled. The shared formFieldBaseClasses + Textarea.tsx local component are the swap target.
• <Field> molecule that wires <label> + <Textarea> + helper / error message slot. Planned post-Select / SearchSelect.
• field-sizing: content auto-grow — interesting CSS proposal but not yet broadly supported; deferred.

🤖 Generated with Claude Code

[chromatic-com]

Tip

All tests passed and all changes approved!

🟢 UI Tests: 7 visual and accessibility changes accepted as baselines
🟢 UI Review: Approved by David Gracia
Storybook Publish: 46 stories published