Logging level overhaul: reduce verbosity at info and debug levels

Per-packet happy-path events (UDP send/receive, TUN I/O, MMP report
processing, TreeAnnounce/FilterAnnounce sent, RTT samples) moved from
debug to trace. Periodic maintenance and retry scheduling moved from
info to debug. Session state changes (established, initiated, torn
down) and transport stop promoted from debug to info. MMP report send
failures demoted from warn to debug (normal under churn).

src/node/bloom.rs

@@ -9,7 +9,7 @@ use crate::NodeAddr;
 
 use super::{Node, NodeError};
 use std::collections::HashMap;
-use tracing::{debug, info};
+use tracing::{debug, trace};
 
 impl Node {
     /// Collect inbound filters from all peers for outgoing filter computation.
@@ -77,7 +77,7 @@ impl Node {
             peer.clear_filter_update_needed();
         }
 
-        debug!(peer = %peer_addr, seq = announce.sequence, "Sent FilterAnnounce");
+        trace!(peer = %peer_addr, seq = announce.sequence, "Sent FilterAnnounce");
         Ok(())
     }
 
@@ -161,7 +161,7 @@ impl Node {
             peer.update_filter(announce.filter, announce.sequence, now_ms);
         }
 
-        info!(
+        debug!(
             from = %from,
             seq = announce.sequence,
             "Received FilterAnnounce"