Restructure into DDD bounded contexts + functional state management

Reorganise from atomic-design-only folders into bounded contexts
(auth / registratie / herregistratie) over a shared kernel, each split into
domain / application / infrastructure / ui layers. Dependencies point inward;
the domain layer is framework-free. Path aliases (@shared/@auth/@registratie/
@herregistratie) make import direction explicit.

State management (Elm-style, native TS, no new deps):
- shared/application/store.ts — createStore(init, update): pure reducer + signal
- shared/application/remote-data.ts — add map/map2/map3/andThen combinators so
  several services fold into one RemoteData; <app-async> gains an [rd] input
- registratie/application/big-profile.store.ts — root singleton combining the
  BIG-register and BRP services via map2 into one state; holds the optimistic
  herregistratie flag shared with the dashboard
- herregistratie: machine gains a WizardMsg union + pure reduce; submit is a
  command that calls infra and dispatches the result, with optimistic update +
  rollback against the shared store
- auth: SessionStore + DigiD adapter + functional route guard; login establishes
  the session, protected routes use canActivate

Rich domain: registration.policy.ts (statusColor/label, herregistratie
eligibility, invariants); BigNummer/Postcode/Uren value objects with smart
constructors. status-badge is now domain-free (colour/label inputs).

Specs for the reducer, RemoteData combinators, and eligibility policy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tsconfig.json

@@ -12,7 +12,15 @@
     "experimentalDecorators": true,
     "importHelpers": true,
     "target": "ES2022",
-    "module": "preserve"
+    "module": "preserve",
+    "ignoreDeprecations": "6.0",
+    "baseUrl": ".",
+    "paths": {
+      "@shared/*": ["src/app/shared/*"],
+      "@auth/*": ["src/app/auth/*"],
+      "@registratie/*": ["src/app/registratie/*"],
+      "@herregistratie/*": ["src/app/herregistratie/*"]
+    }
   },
   "angularCompilerOptions": {
     "enableI18nLegacyMessageIdFormat": false,