[PF-2292] Unlock picass-rich-text-editor React v19

[azebich]

PF-2292

Description

Remove the @emoji-mart/react dependency from @toptal/picasso-rich-text-editor
and render emoji-mart's Picker through a small local component instead, so the
package no longer carries a react peer range that excludes React 19. This
unblocks the peer-cap lift on the PF-2262 branch; Picasso's own react peer is
untouched here.

Why not just upgrade. @emoji-mart/react@1.1.1 is the latest release — last
published January 2023 — and declares react: ^16.8 || ^17 || ^18. No version
exists that supports React 19, so there is nothing to bump to. Relaxing the peer
locally (pnpm patch or peerDependencyRules) would fix only this repo's install:
patches aren't published, so consumers on React 19 would still resolve
@emoji-mart/react@1.1.1 and hit a peer warning or a failed install.

Owning the wrapper is cheap and permanent. It was ~20 lines, exactly one file
imported it, and emoji-mart plus @emoji-mart/data were already direct
dependencies — so nothing is added to the dependency tree, only removed.

The new component (EmojiMartPicker) constructs the Picker on the first
commit and feeds later prop changes through picker.update(props) — both from
effects. The upstream wrapper called update during render, which is a
render-phase side effect; owning the code let us fix that. It also nulls its
instance on unmount.

It is fully typed with no escape hatches: Picker imports from emoji-mart as
both a value and a type, so there is no any and no boundary cast at all. data
is deliberately typed unknown — @emoji-mart/data's .d.ts exports only
interfaces with no default export, so typing it as EmojiMartData would break the
call site.

One call-site change: onClickOutside={showEmojiPicker && closePicker} passed
literal false when closed and now passes undefined. Both are falsy to
emoji-mart, so this is parity rather than a behaviour change.

Not addressed here, deliberately:

• No story that opens the picker. It renders behind opacity-0 until toggled,
  so Happo almost certainly never captures it open. Adding one would genuinely
  improve coverage but moves the visual baseline, so it deserves its own decision.
• SSR is unchanged. emoji-mart calls customElements.define(...) and probes
  canvas at module scope, so importing it needs a DOM. That is pre-existing — the
  old import chain reached the same module — and this change neither improves nor
  worsens it.
• emoji-mart 5.5.2 → 5.6.0 (which would enable the Emoji 15 additions) is
  tracked as a separate follow-up ticket, since it is a user-visible content
  change and not a React 19 blocker.

How to test

• Temploy
• Open the RichText → Default story and use the emoji button in the toolbar:
  the picker opens and closes, standard emojis insert into the editor, and the
  custom emojis from that story's customEmojis still appear and insert.
• Confirm Escape closes the picker, and that clicking outside it closes it.
• Confirm no console errors on open/close/insert.
• Check the Happo report: no visual change is expected.

Note the new unit test proves the picker mounts, but cannot exercise its UI — the
picker's contents live in a shadow DOM that testing-library cannot query. The
manual pass above is the real verification.

Verified locally:

• @emoji-mart/react is gone from the manifest, pnpm-lock.yaml (0 occurrences)
  and node_modules; no reference remains anywhere in the repo
• emoji-mart@5.5.2 and @emoji-mart/data@1.2.1 unchanged — nothing added
• tsc -b --force exit 0 for picasso-rich-text-editor and picasso-forms
  (its only dependent)
• Jest: picasso-rich-text-editor 22 suites / 91 tests pass, run three times with
  identical results; picasso-forms 17 suites / 66 tests / 11 snapshots pass
• ESLint (which runs with --fix) reported nothing and rewrote nothing; Prettier
  clean on all touched files
• The new test is non-vacuous: em-emoji-picker is a custom element only
  emoji-mart creates, so it fails if the picker never mounts

Reviewer note: pnpm typecheck is a no-op in this repo — the root
tsconfig.json is "files": [] plus project references, and tsc --noEmit does
not follow references. Use tsc -b as above.

Screenshots

No visual change is intended — the picker renders the same emoji-mart element as
before, just constructed by our own component. The Happo report is the evidence;
see How to test.

Before.	After.
n/a — no visual change expected	n/a — no visual change expected

Development checks

• Add changeset according to guidelines (if needed) — patch for @toptal/picasso-rich-text-editor: internal implementation change, no public API change
• Double check if picasso-tailwind-merge requires major update (check its README.md) — n/a, no Tailwind or styling changes
• Read CONTRIBUTING.md and Component API principles
• Make sure that additions and changes on the design follow Toptal's BASE design, and it's been already discussed with designers at #-base-core — n/a, no design change
• Annotate all props in component with documentation — the new internal component's props are JSDoc'd; no public props added or changed
• Create examples for component — n/a, no new public component; the picker is already covered by the RichText story
• Ensure that deployed demo has expected results and good examples
• Ensure the changed/created components have not caused accessibility issues. How to use accessibility plugin in storybook.
• Self reviewed
• Covered with tests (visual tests included) — added a mount test for the new component; existing 22 RTE suites and picasso-forms suites pass unchanged; visual coverage via Happo

Breaking change

Not a breaking change — no public API change and no codemod needed. The only
theoretical impact is on a consumer that imported @emoji-mart/react without
declaring it and relied on Picasso hoisting it; such a consumer would now need to
declare it themselves.

• codemod is created and showcased in the changeset
• test alpha package of Picasso in StaffPortal

[changeset-bot]

🦋 Changeset detected

Latest commit: d77af1e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@toptal/picasso-rich-text-editor	Patch
@toptal/picasso-forms	Patch

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