feat(fehlteile): fehlende teile je sammlungseintrag pflegen

Jeder Sammlungseintrag hat jetzt eine Fehlteil-Liste: Teilenummer,
Farbe, Anzahl und Notiz, abhakbar wenn das Teil nachgekauft ist. Ein
Eintrag ohne Nummer geht auch - dann reicht die Notiz, denn beim
Aufbauen kennt man die Nummer selten.

Die Vollstaendigkeit pflegt sich dabei selbst: Der erste offene Eintrag
setzt den Sammlungseintrag auf "Teile fehlen", der letzte erledigte
zurueck auf "vollstaendig". Damit stimmt der Filter in der Sammlung,
ohne dass man daran denken muss.

Offene Fehlteile stehen als Badge an jedem Eintrag - in der Sammlung
und auf der Set-Detailseite.

Refs Phase 2

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/app/(app)/katalog/[id]/page.tsx

@@ -18,6 +18,7 @@ import {
   listInstructionsForSet,
   listPhotosForSet,
 } from '@/lib/queries/catalog';
+import { listMissingParts } from '@/lib/queries/collection';
 import { listLocations } from '@/lib/queries/master-data';
 import { listWishlistsForSet, listWishlistTargets } from '@/lib/queries/wishlists';
 import { requireUser } from '@/lib/session';
@@ -45,6 +46,8 @@ export default async function SetDetailPage({ params }: Props) {
   const collectionItems = listCollectionItemsForSet(set.id).map((item) => ({
     ...item,
     locationName: item.locationId ? (locationNames.get(item.locationId) ?? null) : null,
+    setName: `${set.setNumber} · ${set.name}`,
+    missingParts: listMissingParts(item.id),
   }));
 
   const facts: Array<[string, string]> = [

src/app/(app)/sammlung/actions.ts

@@ -1,9 +1,9 @@
 'use server';
 
 import { revalidatePath } from 'next/cache';
-import { eq } from 'drizzle-orm';
+import { and, eq } from 'drizzle-orm';
 import { db } from '@/db';
-import { collectionItem, set } from '@/db/schema';
+import { collectionItem, missingPart, set } from '@/db/schema';
 import {
   actionData,
   actionError,
@@ -13,7 +13,7 @@ import {
 } from '@/lib/action-result';
 import { reconcileFulfilledWishlistItems } from '@/lib/queries/wishlists';
 import { requireUser } from '@/lib/session';
-import { collectionItemSchema } from '@/lib/validation';
+import { collectionItemSchema, missingPartSchema } from '@/lib/validation';
 import type { Condition } from '@/db/types';
 
 function now() {
@@ -103,3 +103,123 @@ export async function deleteCollectionItem(id: string): Promise<ActionResult> {
   revalidateCollection(existing.setId);
   return actionOk();
 }
+
+// ---------------------------------------------------------------------------
+// Missing parts
+// ---------------------------------------------------------------------------
+
+/**
+ * Keeps `completeness` honest without ever fighting the user.
+ *
+ * The moment a part is reported missing the item is not complete any more, and
+ * once the last open entry is resolved it is complete again. A deliberate
+ * "unknown" is left alone in the second direction only.
+ */
+function syncCompleteness(collectionItemId: string): void {
+  const open = db
+    .select({ id: missingPart.id })
+    .from(missingPart)
+    .where(and(eq(missingPart.collectionItemId, collectionItemId), eq(missingPart.resolved, false)))
+    .all();
+
+  const item = db
+    .select({ completeness: collectionItem.completeness })
+    .from(collectionItem)
+    .where(eq(collectionItem.id, collectionItemId))
+    .get();
+  if (!item) return;
+
+  if (open.length > 0 && item.completeness !== 'missing_parts') {
+    db.update(collectionItem)
+      .set({ completeness: 'missing_parts', updatedAt: now() })
+      .where(eq(collectionItem.id, collectionItemId))
+      .run();
+    return;
+  }
+
+  if (open.length === 0 && item.completeness === 'missing_parts') {
+    db.update(collectionItem)
+      .set({ completeness: 'complete', updatedAt: now() })
+      .where(eq(collectionItem.id, collectionItemId))
+      .run();
+  }
+}
+
+function loadItemSetId(collectionItemId: string): string | null {
+  const row = db
+    .select({ setId: collectionItem.setId })
+    .from(collectionItem)
+    .where(eq(collectionItem.id, collectionItemId))
+    .get();
+  return row?.setId ?? null;
+}
+
+export async function addMissingPart(
+  collectionItemId: string,
+  input: unknown,
+): Promise<ActionResult> {
+  await requireUser();
+
+  const parsed = parseForm(missingPartSchema, input);
+  if (!parsed.ok) return parsed;
+
+  const setId = loadItemSetId(collectionItemId);
+  if (!setId) return actionError('Diesen Sammlungseintrag gibt es nicht mehr.');
+
+  db.insert(missingPart)
+    .values({
+      id: crypto.randomUUID(),
+      collectionItemId,
+      partNumber: parsed.data.partNumber,
+      colorName: parsed.data.colorName,
+      quantity: parsed.data.quantity,
+      resolved: false,
+      notes: parsed.data.notes,
+      createdAt: now(),
+    })
+    .run();
+
+  syncCompleteness(collectionItemId);
+  revalidateCollection(setId);
+  return actionOk();
+}
+
+export async function setMissingPartResolved(
+  missingPartId: string,
+  resolved: boolean,
+): Promise<ActionResult> {
+  await requireUser();
+
+  const row = db
+    .select({ collectionItemId: missingPart.collectionItemId })
+    .from(missingPart)
+    .where(eq(missingPart.id, missingPartId))
+    .get();
+  if (!row) return actionOk();
+
+  db.update(missingPart)
+    .set({ resolved })
+    .where(eq(missingPart.id, missingPartId))
+    .run();
+
+  syncCompleteness(row.collectionItemId);
+  revalidateCollection(loadItemSetId(row.collectionItemId) ?? undefined);
+  return actionOk();
+}
+
+export async function deleteMissingPart(missingPartId: string): Promise<ActionResult> {
+  await requireUser();
+
+  const row = db
+    .select({ collectionItemId: missingPart.collectionItemId })
+    .from(missingPart)
+    .where(eq(missingPart.id, missingPartId))
+    .get();
+  if (!row) return actionOk();
+
+  db.delete(missingPart).where(eq(missingPart.id, missingPartId)).run();
+
+  syncCompleteness(row.collectionItemId);
+  revalidateCollection(loadItemSetId(row.collectionItemId) ?? undefined);
+  return actionOk();
+}

src/app/(app)/sammlung/page.tsx

@@ -10,6 +10,7 @@ import { completenessLabel, statusLabel } from '@/lib/labels';
 import { formatEuro } from '@/lib/money';
 import {
   countMissingSets,
+  countOpenMissingParts,
   getCollectionStats,
   listCollectionItems,
   type CollectionFilters as Filters,
@@ -40,6 +41,7 @@ export default async function SammlungPage({ searchParams }: { searchParams: Sea
   };
 
   const items = listCollectionItems(filters);
+  const openParts = countOpenMissingParts(items.map((item) => item.id));
   const stats = getCollectionStats();
   const missing = countMissingSets();
 
@@ -132,6 +134,9 @@ export default async function SammlungPage({ searchParams }: { searchParams: Sea
                       {item.completeness !== 'unknown' ? (
                         <Badge variant="secondary">{completenessLabel(item.completeness)}</Badge>
                       ) : null}
+                      {openParts.get(item.id) ? (
+                        <Badge variant="outline">{openParts.get(item.id)} Fehlteile</Badge>
+                      ) : null}
                       {item.acquiredAt ? (
                         <span className="text-xs text-muted-foreground">
                           seit {formatDate(item.acquiredAt)}