Move the console onto ReUI PRO

Install ReUI (MCP, skill, @reui registry, Tailwind v4, shadcn base-nova) and move
the shared UI onto it: Button, Tag, Check, Input/Textarea, Segmented, Alert, Panel,
Dialog, Tooltip, Menu and Select (Popover), Toast (sonner), the Table frame
(DataGrid), the Dashboard KPI strip, the shnt Ops palette, Geist and the type scale.

Design only: behaviour, texts and roles are unchanged. Tests that asserted the old
DOM were updated; the tests now format numbers in English wherever they run.
docs/reui-migration-plan.md records the plan and its decisions.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/ui/Check.module.css

@@ -0,0 +1,45 @@
+.check {
+  display: flex;
+  align-items: flex-start;
+  gap: var(--s-6);
+  /* The label IS the target: it is clicked from the text, not only from the box.
+     At 22 px tall it fell short for a finger. */
+  min-height: 26px;
+  padding: var(--s-2) 0;
+  font-size: var(--t-4);
+  cursor: pointer;
+}
+
+/* The box aligns with the label's first line, not with its box. */
+.text { min-width: 0; }
+
+.help {
+  composes: withCode from './text.module.css';
+  font-size: var(--t-3);
+  color: var(--mute);
+  line-height: 1.55;
+  margin-top: var(--s-3);
+  margin-left: calc(var(--ctrl) + var(--s-6));
+  /*
+  720 px, and **it is a local exception with its figure**, not a missing token.
+
+  Decided 2026-09-03, in a design review. Measured
+  first: **it really bites**. At 1920, with the control column at 1022 px, the nine
+  checkbox helps of `Settings › General` come out at exactly 720, so it is not dead
+  code that can be deleted.
+
+  And it does not go up to `tokens.css` for the same reason the Dashboard hero did
+  not: **only this uses it**. A global token is declared when two places share a
+  decision; declaring one for a single use is inventing vocabulary nobody speaks.
+
+  What the cap is and why it is not `--help-col`: this is **the only help the
+  dense-form design did NOT move** to the third column. A checkbox's stays under its control
+  (because the checkbox IS its label and separating them would break that unit), so
+  it inherits the control column's width, which on wide screens goes well past
+  what reads comfortably. 720 is the readable line cap for THIS case.
+
+  If some day a second help stays out of the third column, then there are two and
+  a token is due; today there are nine from the same place.
+  */
+  max-width: 720px;
+}