feat(ui): drop @nstart/ui dependency (Stage 3.9)

Все font cascade bugs из последних MR были вызваны @nstart/ui pollution
(Tektur inheritance от Card parent'ов, Onest font в Button, font-primary
class overrides). Решили обрезать раньше plan'а.

What changed:

New primitives (8 файлов в src/ui/components/):
  - panel.tsx           — container с border/surface
  - field.tsx           — FieldLabel/Hint/Error typography helpers
  - text-input.tsx      — Input + label/hint/error composite
  - table.tsx           — Table/TableHeader/Body/Row/HeaderCell/Cell/Empty
  - date-picker.tsx     — native <input type=date> wrapper с label/hint/error
  - multi-select.tsx    — Radix Popover + inline checkboxes
  - single-select.tsx   — native <select> с label/hint/error chrome
  - language-switch.tsx — segmented control в Tektur uppercase

Compatibility shims (existing components extended):
  - checkbox.tsx        — + label/description/error/onChange (nstart-compat
                          synthetic event), wrap в <label> когда есть chrome
  - modal.tsx           — + panelClassName / bodyClassName props
  - form-actions.tsx    — + align prop (start/end/between)
  - tabs-simple.tsx     — TabItem.count alias for .trailing (nstart-compat)
  - table TableHead     — alias TableHeaderCell с align prop

Barrel rewrite (src/ui/index.ts):
  - Удалён 'export * from @nstart/ui'
  - Explicit exports для всех 45+ нужных символов
  - SelectOption / MultiSelectOption / LanguageOption теперь {id, label}
    с optional 'value' alias — nstart-compat без массового codemod call-sites

styles.css cleanup:
  - Removed @import @nstart/ui/styles/{fonts,theme}.css
  - Removed @source nstart/dist directive (Tailwind v4 scan)
  - Removed --text-sm: 13px override (был костыль для @nstart/ui dist)
  - Legacy color tokens (--color-carbon/ultramarain/orbit/regolith/asteroid)
    sсодержали fallback mappings — оставлены, но callsites больше не используют

Codemod: 9 файлов конвертированы legacy colors → handoff tokens
  carbon → ink, ultramarain → accent, orbit → warn, regolith → line, asteroid → mute

main.tsx:
  - NStartUiProvider → TooltipProvider (Radix)
  - DatePickerProvider убран (наш DatePicker native, no provider needed)

routes/dictionaries.$name.tsx:
  - Removed useRef-based <input>.indeterminate hack
  - Radix Checkbox принимает checked='indeterminate' declaratively

package.json: -@nstart/ui (was 0.1.3)

Bundle impact:
  before: vendor-nstart-ui chunk = 1228 KB
  after:  no nstart chunk, всё в vendor-misc (+~70 KB Radix wrappers)
  net savings: ~1.15 MB minified, ~440 KB gzip

Tests: 116 pass (1 fixed: tab role from 'button' → 'tab', Radix semantically correct).
TS strict: clean.
Browser-verified (preview): 7 utilities computed correctly, nstart bundle absent.

ordinis-admin-ui/src/routes/webhooks.$id.tsx

@@ -235,7 +235,7 @@ function WebhookDetailPage() {
  'text-cap inline-flex items-center gap-1.5 px-2.5 py-1 rounded-sm border transition-colors',
                   active
                     ? 'border-accent bg-accent/8 text-accent'
-                    : 'border-line bg-white text-ink-2 hover:border-carbon/40',
+                    : 'border-line bg-white text-ink-2 hover:border-ink/40',
                 ].join(' ')}
               >
                 {s}
@@ -452,7 +452,7 @@ function RotateRevealModal({
         <Alert variant="warning" title={t('webhooks.secret.warningTitle')}>
           {t('webhooks.secret.rotatedWarning')}
         </Alert>
-        <div className="bg-carbon/5 border border-line rounded-md p-3">
+        <div className="bg-ink/5 border border-line rounded-md p-3">
           <code className="text-mono break-all">{secret}</code>
         </div>
         <div className="flex justify-end">