refactor(registratie): extract the read half of createDraftSync (RB-21)

createDraftSync mixed a read path (findConcept, load, the read half of
resume) with its write path (ensureId, flush, submit, reset) in one
187-line function -- CQ-001's finding. Move findConcept and loadConcept
into a new application/find-concept.ts as free functions that take the
adapter, so they get a direct spec with no Angular TestBed.

createDraftSync keeps the closure state (id, ensuring, resumeGate) and
the whole write path unchanged -- this is a move, not a redesign. The
resumeGate coupling that lets the write path wait for the read path
stays exactly where it was.

createDraftSync shrinks from 187 to 169 lines. draft-sync.spec.ts is
unchanged -- it never called resume()/load() directly, and its 409
recovery test for submit() still exercises the extracted findConcept
through ensureId's catch branch.

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

apps/ssp/src/app/registratie/application/draft-sync.ts

@@ -8,10 +8,8 @@ import type {
   SubmitApplicationResponse,
 } from '@shared/infrastructure/api-client';
 import { AanvraagType } from '@registratie/domain/aanvraag';
-import {
-  ApplicationsAdapter,
-  parseApplications,
-} from '@registratie/infrastructure/applications.adapter';
+import { ApplicationsAdapter } from '@registratie/infrastructure/applications.adapter';
+import { findConcept, loadConcept } from './find-concept';
 
 /** What a wizard persists per step: the opaque machine snapshot + progress + docs. */
 export interface DraftSnapshot {
@@ -70,7 +68,7 @@ export function createDraftSync(deps: DraftSyncDeps) {
       // server's guard (409) — recover by adopting the existing Concept instead of
       // erroring. Only recover when one actually exists; otherwise surface the failure.
       .catch(async (e) => {
-        const existing = await findConcept();
+        const existing = await findConcept(adapter, deps.type);
         if (existing) return existing;
         throw e;
       })
@@ -140,32 +138,14 @@ export function createDraftSync(deps: DraftSyncDeps) {
   // (submitted/gone) id is treated as fresh so it can't reopen as an editable draft.
   const load = (linked: string): Promise<void> => {
     id = linked;
-    return adapter
-      .detail(linked)
-      .then((dto) => {
-        if (dto.status && dto.status.tag !== 'Concept') {
-          id = undefined;
-          applyResume(null);
-          return;
-        }
-        applyResume(dto.draft ?? null);
-      })
-      .catch(() => {
+    return loadConcept(adapter, linked).then((result) => {
+      if (result.tag === 'not-concept') {
         id = undefined;
-        applyResume(null); // unknown/deleted id → start fresh
-      });
-  };
-
-  // Find the user's existing Concept of this type (at most one), if any.
-  const findConcept = async (): Promise<string | undefined> => {
-    try {
-      const parsed = parseApplications(await adapter.list());
-      return parsed.ok
-        ? parsed.value.find((a) => a.type === deps.type && a.status.tag === 'Concept')?.id
-        : undefined;
-    } catch {
-      return undefined;
-    }
+        applyResume(null);
+        return;
+      }
+      applyResume(result.draft);
+    });
   };
 
   return {
@@ -189,7 +169,7 @@ export function createDraftSync(deps: DraftSyncDeps) {
           await load(linked);
           return;
         }
-        const existing = await findConcept();
+        const existing = await findConcept(adapter, deps.type);
         if (existing) {
           await load(existing);
           // Stamp the id into the URL so a reload resumes the same Concept.