feat(behandelportal): WP-64 werkvoorraad (queue) screen

New GET /werkvoorraad endpoint lists aanvragen still open (Ingediend/InBehandeling),
gated by the medewerker capability (CanBeoordelen) rather than the admin role — reuses
the existing ApplicationSummaryDto, no new DTO. GET /me now surfaces aanvraag:beoordelen
for a behandelaar so the FE can gate with the same AccessStore/capabilityGuard idiom
every other page uses.

FE: a behandeling domain type deliberately narrower than ssp's full AanvraagStatus
union (only the two open tags — illegal states unrepresentable), composed into a
werkvoorraad-list organism from existing shared/ui molecules. Replaces WP-61's
scaffold placeholder as the app's real landing page.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

libs/shared/src/domain/capability.ts

@@ -9,4 +9,5 @@ export type Capability =
   | 'orgtemplate:edit'
   | 'stamdata:edit'
   | 'cases:manage'
-  | 'flags:manage';
+  | 'flags:manage'
+  | 'aanvraag:beoordelen';