fix(acadenice): sync-block date string + graph p.slug column name — Patch 026

Two server bugs surfaced from the live test:

1. SyncBlockRepo.mapRow crashed with 'Cannot read properties of
   undefined (reading toISOString)' on POST /api/acadenice/sync-blocks.
   The kysely-postgres-js driver returns timestamps as strings, not
   Date instances. Wrap with new Date(...) before .toISOString().

2. GraphService.loadPageMeta + loadOrphanPages SELECT'd p.slug, but the
   native pages table column is named slug_id. Postgres rejected the
   query, the catch returned [], and the graph rendered empty even when
   pages existed. Aliased p.slug_id AS slug to match the PageMetaRow
   interface.

Patch 026.

apps/server/src/core/acadenice/graph/services/graph.service.ts

@@ -434,7 +434,7 @@ export class GraphService {
         SELECT
           p.id,
           p.title,
-          p.slug,
+          p.slug_id AS slug,
           p.space_id,
           sp.name AS space_name,
           p.icon
@@ -479,7 +479,7 @@ export class GraphService {
         SELECT
           p.id,
           p.title,
-          p.slug,
+          p.slug_id AS slug,
           p.space_id,
           sp.name AS space_name,
           p.icon

apps/server/src/core/acadenice/sync-blocks/repos/sync-block.repo.ts

@@ -181,16 +181,16 @@ export class SyncBlockRepo {
     workspace_id: string;
     content: Record<string, unknown>;
     created_by: string;
-    created_at: Date;
-    updated_at: Date;
+    created_at: Date | string;
+    updated_at: Date | string;
   }): SyncBlockResponseDto {
     return {
       id: row.id,
       workspaceId: row.workspace_id,
       content: row.content,
       createdBy: row.created_by,
-      createdAt: row.created_at.toISOString(),
-      updatedAt: row.updated_at.toISOString(),
+      createdAt: new Date(row.created_at).toISOString(),
+      updatedAt: new Date(row.updated_at).toISOString(),
     };
   }
 }