fix: rebuild FTS5 index after database rebuild to prevent stale rowid refs

The FTS5 content-synced index could retain phantom rowid references from
previous rebuild cycles, causing 'missing row N from content table'
errors on MATCH queries.

- Add explicit FTS5 rebuild command in rebuild script after all nodes saved
- Add FTS5 rebuild in test beforeAll as defense-in-depth
- Rebuild nodes.db with consistent FTS5 index

Conceived by Romuald Członkowski - www.aiadvisors.pl/en

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/integration/database/node-fts5-search.test.ts

@@ -17,6 +17,12 @@ describe('Node FTS5 Search Integration Tests', () => {
     const testDbPath = './data/nodes.db';
     db = await createDatabaseAdapter(testDbPath);
     repository = new NodeRepository(db);
+
+    // Rebuild FTS5 index to ensure it is in sync with the nodes table.
+    // The content-synced FTS5 index (content=nodes) can become stale if the
+    // database was rebuilt without an explicit FTS5 rebuild command, leaving
+    // phantom rowid references that cause "missing row" errors on MATCH queries.
+    db.prepare("INSERT INTO nodes_fts(nodes_fts) VALUES('rebuild')").run();
   });
 
   afterAll(() => {