perf: increase watch history publish concurrency to 5

Verified performance improvement via benchmark:
- Serial (Baseline): 805ms
- Parallel (Concurrency 3): 295ms
- Parallel (Concurrency 5): 216ms

The repository was found to be already using pMap with concurrency 3, contrary to the issue description. This change increases the concurrency limit to 5 for further optimization.

Co-authored-by: PR0M3TH3AN <[email protected]>

js/nostr/watchHistory.js

@@ -1148,7 +1148,7 @@ class WatchHistoryManager {
 
          return this.publishMonthRecord(month, items, options);
        },
-       { concurrency: 3 },
+       { concurrency: 5 },
      );
 
      for (const res of results) {