feat(npcs): add groups, storyline bindings, and Foundry import

Nested NPC groups with color, graph filter, and scene/storyline binding; Foundry worlds/modules import actors into groups; storyline merge asks on NPC name conflicts and reports NPC counts.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/npcs/npcListHelpers.ts

@@ -0,0 +1,95 @@
+import type { NpcGroupId, NpcId, ProjectNpc, ProjectNpcGroup } from '../../shared/types';
+
+export function reorderNpcIds(
+  npcs: ProjectNpc[],
+  dragId: NpcId,
+  targetId: NpcId,
+  place: 'before' | 'after',
+): NpcId[] {
+  const ids = npcs.map((n) => n.id);
+  const from = ids.indexOf(dragId);
+  if (from < 0) return ids;
+  ids.splice(from, 1);
+  let to = ids.indexOf(targetId);
+  if (to < 0) return npcs.map((n) => n.id);
+  if (place === 'after') to += 1;
+  ids.splice(to, 0, dragId);
+  return ids;
+}
+
+/** Move NPC to end of its group block in global order. */
+export function moveNpcToGroupEnd(npcs: ProjectNpc[], dragId: NpcId, groupId: NpcGroupId | null): NpcId[] {
+  const updated = npcs.map((n) => (n.id === dragId ? { ...n, groupId } : n));
+  const ids = updated.map((n) => n.id);
+  const from = ids.indexOf(dragId);
+  if (from < 0) return ids;
+  ids.splice(from, 1);
+
+  let insertAt = ids.length;
+  for (let i = ids.length - 1; i >= 0; i -= 1) {
+    const npc = updated.find((n) => n.id === ids[i]);
+    if (npc?.groupId === groupId) {
+      insertAt = i + 1;
+      break;
+    }
+  }
+  if (groupId === null) {
+    for (let i = ids.length - 1; i >= 0; i -= 1) {
+      const npc = updated.find((n) => n.id === ids[i]);
+      if (npc?.groupId === null) {
+        insertAt = i + 1;
+        break;
+      }
+    }
+  }
+  ids.splice(insertAt, 0, dragId);
+  return ids;
+}
+
+export function reorderSiblingGroups(
+  groups: ProjectNpcGroup[],
+  dragId: NpcGroupId,
+  targetId: NpcGroupId,
+  place: 'before' | 'after',
+): NpcGroupId[] {
+  const drag = groups.find((g) => g.id === dragId);
+  const target = groups.find((g) => g.id === targetId);
+  if (!drag || drag.parentId !== target?.parentId) return groups.map((g) => g.id);
+
+  const parentId = drag.parentId;
+  const siblingIds = groups.filter((g) => g.parentId === parentId).map((g) => g.id);
+  const from = siblingIds.indexOf(dragId);
+  if (from < 0) return groups.map((g) => g.id);
+  siblingIds.splice(from, 1);
+  let to = siblingIds.indexOf(targetId);
+  if (to < 0) return groups.map((g) => g.id);
+  if (place === 'after') to += 1;
+  siblingIds.splice(to, 0, dragId);
+
+  const result: NpcGroupId[] = [];
+  let inserted = false;
+  for (const g of groups) {
+    if (g.parentId === parentId) {
+      if (!inserted) {
+        result.push(...siblingIds);
+        inserted = true;
+      }
+      continue;
+    }
+    result.push(g.id);
+  }
+  return result;
+}
+
+export function flattenGroupOptions(
+  nodes: { group: ProjectNpcGroup; children: unknown[] }[],
+  depth = 0,
+): { id: NpcGroupId; label: string }[] {
+  const out: { id: NpcGroupId; label: string }[] = [];
+  for (const node of nodes) {
+    const prefix = depth > 0 ? '  '.repeat(depth) : '';
+    out.push({ id: node.group.id, label: `${prefix}${node.group.name}` });
+    out.push(...flattenGroupOptions(node.children as typeof nodes, depth + 1));
+  }
+  return out;
+}