fix(knowledge): start the scan budget over when the pages are rebuilt

The candidates already seen before a denied source was known are skipped when the pages are rebuilt, but they still counted against the scan budget, so a refill could exhaust it before reaching the readable candidates ranked after the denied source.

Author: waleedlatif1

apps/sim/lib/knowledge/search/queries.ts

@@ -743,7 +743,9 @@ async function selectAuthorizedSearchResults(input: {
         for (const row of ranked) results.set(row.id, row)
       }
       if (refill) {
+        /** The rebuilt pages are a new stream of candidates, so the scan budget starts over. */
         offset = 0
+        scanned = 0
         continue
       }
       /** A short page is the end of the candidates, whether or not they were reordered. */