Seed relay: compressed overviews by default again

Measured with 20 relay connections, plain and gzip both gave ~1.5 chunks/s
for 2026 a.b.ath articles; plain used many times the CPU and traffic.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/services/SeedFetchPool.ts

@@ -31,8 +31,7 @@ class SeedFetchPool {
   }
 
   /**
-   * Pooled connections fetch compressed only with SEED_NNTP_COMPRESS (plain is
-   * faster for recent articles). A failure is retried once without compression, on a connection of its
+   * Pooled connections fetch compressed unless SEED_NNTP_COMPRESS=false. A failure is retried once without compression, on a connection of its
    * own: either the pooled connection was dead (dropped while idle), or the
    * server stalled mid-reply in compressed mode. Eweka does that for some
    * chunks: it stops after most of the stream and never sends the rest