Reorganize twenty-ui into best-practice component domains and per-component folders (#21745)

Reorganizes `twenty-ui`'s component organization to follow how the best
UI libraries (MUI, Mantine, Base UI, Polaris) structure their source,
now that the package has stabilized.

**Taxonomy** — dissolves the meaningless `components/` junk-drawer and
the 107-file `display/` mega-category. New domains/subpaths:
`data-display`, `typography`, `icon`, `surfaces`; `feedback` and
`layout` absorb the rest (banners/callout/info + placeholders →
feedback; modal/card → surfaces; motion + separators → layout).

**Per-component layout** — every component is now
`<domain>/<ComponentName>/<ComponentName>.tsx` with colocated
styles/stories/types, `internal/` for private helpers and `parts/` for
re-exported compound sub-parts. The redundant inner `/components/` is
gone. `icon` and `json-visualizer` are kept as cohesive subsystems.

**Also:** adds a tree-shakeable root barrel (`import { Button } from
'twenty-ui'`), the generator now owns `individual-entry.ts`, and a real
barrel-leak bug is fixed (private `internals/` parts were leaking into
the public API).

Consumer imports (~1.2k files) and the `twenty-sdk` UI aggregator were
updated by codemod. The change is **export-neutral** except 16
intentionally-removed private internals symbols (all verified
unconsumed). Gates green: typecheck, lint, build, size-limit, storybook.


<!-- This is an auto-generated description by cubic. -->
<a
href="https://cubic.dev/pr/twentyhq/twenty/pull/21745?utm_source=github"
target="_blank" rel="noopener noreferrer"
data-no-image-dialog="true"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source
media="(prefers-color-scheme: light)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img
alt="Review in cubic"
src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>
<!-- End of auto-generated description by cubic. -->

packages/twenty-ui/src/data-display/NotificationCounter/NotificationCounter.module.scss

@@ -0,0 +1,20 @@
+.notificationCounter {
+  width: 14px;
+  height: 14px;
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: var(--t-font-size-xxs);
+  font-weight: var(--t-font-weight-semi-bold);
+}
+
+.primary {
+  background: var(--t-color-blue);
+  color: white;
+}
+
+.secondary {
+  background: var(--t-background-transparent-light);
+  color: var(--t-font-color-secondary);
+}

packages/twenty-ui/src/data-display/NotificationCounter/NotificationCounter.module.scss.d.ts

@@ -0,0 +1,6 @@
+declare const classNames: {
+  readonly notificationCounter: 'notificationCounter';
+  readonly primary: 'primary';
+  readonly secondary: 'secondary';
+};
+export default classNames;

packages/twenty-ui/src/data-display/NotificationCounter/NotificationCounter.tsx

@@ -0,0 +1,23 @@
+import { clsx } from 'clsx';
+
+import styles from './NotificationCounter.module.scss';
+
+type NotificationCounterProps = {
+  count: number;
+  variant?: 'primary' | 'secondary';
+  className?: string;
+};
+
+export const NotificationCounter = ({
+  count,
+  variant = 'primary',
+  className,
+}: NotificationCounterProps) => {
+  return (
+    <div
+      className={clsx(styles.notificationCounter, styles[variant], className)}
+    >
+      {count}
+    </div>
+  );
+};