Allow two case-number formats: NNNN-YY and NNNN-MM-YY

Narrow the regex to exactly the two hyphen-separated shapes Dafna
uses in practice (1033-25, 1000-04-26). Wider shapes like "1033-foo"
are rejected too — they didn't exist in any real case and would
quietly widen the surface area for routing bugs later.

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

web-ui/src/components/wizard/case-wizard.tsx

@@ -123,7 +123,7 @@ export function CaseWizard() {
                 </Label>
                 <Input
                   id="case_number"
-                  placeholder="1234 או 8001/2026"
+                  placeholder="1033-25 או 1000-04-26"
                   {...form.register("case_number")}
                   className="mt-1 tabular-nums"
                 />