Fix: late draft-resume no longer clobbers in-progress wizard input

draftSync.resume() does async network work and dispatched Seed on completion,
which could land after the user's first action and reset the machine (cursor +
fields) — the "click Volgende twice" symptom. Guard centrally: applyResume()
skips when the user already has progress (snapshot() != null) or there's nothing
to restore. onResume is now only ever called with a real draft on a pristine
machine, so the three wizard callbacks drop the dead `?? initial`.

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

src/app/herregistratie/ui/herregistratie-wizard/herregistratie-wizard.component.ts

@@ -102,7 +102,7 @@ export class HerregistratieWizardComponent {
       const documentIds = deliveryRefs(s.upload).filter((r) => r.channel === 'digital' && r.documentId).map((r) => r.documentId!);
       return { draft: s, stepIndex: s.step - 1, stepCount: this.stepLabels.length, documentIds };
     },
-    onResume: (draft) => this.dispatch({ tag: 'Seed', state: (draft as WizardState | null) ?? initial }),
+    onResume: (draft) => this.dispatch({ tag: 'Seed', state: draft as WizardState }),
     enabled: () => this.seed() === initial,
   });
 

src/app/herregistratie/ui/intake-wizard/intake-wizard.component.ts

@@ -131,7 +131,7 @@ export class IntakeWizardComponent {
       if (s.tag !== 'Answering' || !hasProgress(s)) return null;
       return { draft: s, stepIndex: s.cursor, stepCount: STEPS.length, documentIds: [] };
     },
-    onResume: (draft) => this.dispatch({ tag: 'Seed', state: (draft as IntakeState | null) ?? initial }),
+    onResume: (draft) => this.dispatch({ tag: 'Seed', state: draft as IntakeState }),
     enabled: () => this.seed() === initial,
   });
 

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

@@ -18,8 +18,9 @@ export interface DraftSyncDeps {
   type: AanvraagType;
   /** The machine snapshot while it's worth persisting; null when not (pristine/done). */
   snapshot: () => DraftSnapshot | null;
-  /** Seed the machine from a resumed draft (null → start fresh). Called once, on init. */
-  onResume: (draft: unknown | null) => void;
+  /** Seed the machine from a resumed draft. Called at most once, on init, and ONLY
+      with a real draft on a still-pristine machine — see `applyResume`. */
+  onResume: (draft: unknown) => void;
   /** Draft-sync only runs in the real app — false in Storybook/tests (explicit seed). */
   enabled: () => boolean;
 }
@@ -64,6 +65,15 @@ export function createDraftSync(deps: DraftSyncDeps) {
     return ensuring;
   };
 
+  // Apply a resumed draft only when it's safe to: a late lookup must never clobber
+  // progress the user already made while it was in flight, and "start fresh" needs no
+  // dispatch (the machine already starts fresh). snapshot() is non-null once the user
+  // has real progress.
+  const applyResume = (draft: unknown | null) => {
+    if (draft == null || deps.snapshot() != null) return;
+    deps.onResume(draft);
+  };
+
   const flush = async () => {
     const snap = deps.snapshot();
     if (!snap) return;
@@ -92,14 +102,14 @@ export function createDraftSync(deps: DraftSyncDeps) {
       .then((dto) => {
         if (dto.status && dto.status.tag !== 'Concept') {
           id = undefined;
-          deps.onResume(null);
+          applyResume(null);
           return;
         }
-        deps.onResume(dto.draft ?? null);
+        applyResume(dto.draft ?? null);
       })
       .catch(() => {
         id = undefined;
-        deps.onResume(null); // unknown/deleted id → start fresh
+        applyResume(null); // unknown/deleted id → start fresh
       });
   };
 
@@ -121,7 +131,7 @@ export function createDraftSync(deps: DraftSyncDeps) {
       resumeGate = new Promise<void>((r) => (release = r));
       try {
         if (!active()) {
-          deps.onResume(null);
+          applyResume(null);
           return;
         }
         const linked = route!.snapshot.queryParamMap.get('aanvraag');
@@ -136,7 +146,7 @@ export function createDraftSync(deps: DraftSyncDeps) {
           void router!.navigate([], { relativeTo: route!, queryParams: { aanvraag: existing }, queryParamsHandling: 'merge', replaceUrl: true });
           return;
         }
-        deps.onResume(null);
+        applyResume(null);
       } finally {
         release();
       }