Phase 4a: shadcn form primitives + case inline edit

Add dialog/select/textarea/label/progress/sonner components and wire
a Toaster into Providers. New zod schemas in lib/schemas/case.ts
mirror CaseCreateRequest/CaseUpdateRequest and feed react-hook-form
validation.

CaseEditDialog on the case detail Actions tab posts PUT /api/cases/{n}
with optimistic cache patching via useUpdateCase, showing toast
feedback on success/error.

shadcn's <Form> registry entry skipped at init (missing from the
nova preset); the dialog uses RHF directly against the same Input/
Textarea/Select primitives.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web-ui/src/components/ui/label.tsx

@@ -0,0 +1,24 @@
+"use client"
+
+import * as React from "react"
+import { Label as LabelPrimitive } from "radix-ui"
+
+import { cn } from "@/lib/utils"
+
+function Label({
+  className,
+  ...props
+}: React.ComponentProps<typeof LabelPrimitive.Root>) {
+  return (
+    <LabelPrimitive.Root
+      data-slot="label"
+      className={cn(
+        "flex items-center gap-2 text-sm leading-none font-medium select-none group-data-[disabled=true]:pointer-events-none group-data-[disabled=true]:opacity-50 peer-disabled:cursor-not-allowed peer-disabled:opacity-50",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Label }