proto/bloom: relocate bloom filter into sans-IO layout

Migrate the v1 bloom filter subsystem into src/proto/bloom/, matching the
discovery/routing/fmp/mmp/stp reference layout and completing the proto/
relocation series for the data/wire subsystems.

- wire.rs: the FilterAnnounce (0x20) codec, moved from protocol/filter.rs
- core.rs: the pure BloomFilter algorithm (hash/insert/contains/merge/
  as_bytes/from_bytes/estimated_count), moved from bloom/filter.rs
- state.rs: BloomState (per-peer inbound store, compute_outgoing_filter,
  the injected-clock send debounce), moved from bloom/state.rs
- limits.rs: the v1 sizing constants
- mod.rs: module wiring + the BloomError enum
- tests/: the unit suite split by target (core/state/wire), no inline tests

no_std+alloc hygiene: core::fmt over std::fmt, the tracing dependency
dropped from the pure filter, and std collections replaced with
BTreeMap/BTreeSet (NodeAddr: Ord) for deterministic iteration. The pure
filter combination stays a BloomState method; the two irreducible shell
gathers (peer_inbound_filters, build_filter_announce) remain in the async
shell. Wire bytes and observable behavior are unchanged; full local CI
green (36/36) including the bloom-storm chaos gate.

src/node/bloom.rs

@@ -4,12 +4,12 @@
 //! including debounced propagation to peers.
 
 use crate::NodeAddr;
-use crate::bloom::BloomFilter;
-use crate::protocol::FilterAnnounce;
+use crate::proto::bloom::BloomFilter;
+use crate::proto::bloom::FilterAnnounce;
 
 use super::reject::BloomReject;
 use super::{Node, NodeError};
-use std::collections::HashMap;
+use std::collections::BTreeMap;
 use tracing::{debug, warn};
 
 impl Node {
@@ -17,8 +17,8 @@ impl Node {
     ///
     /// Returns a map of (peer_node_addr -> filter) for peers that
     /// have sent us a FilterAnnounce.
-    pub(super) fn peer_inbound_filters(&self) -> HashMap<NodeAddr, BloomFilter> {
-        let mut filters = HashMap::new();
+    pub(super) fn peer_inbound_filters(&self) -> BTreeMap<NodeAddr, BloomFilter> {
+        let mut filters = BTreeMap::new();
         for (addr, peer) in &self.peers {
             if self.is_tree_peer(addr)
                 && let Some(filter) = peer.inbound_filter()

src/node/mod.rs

@@ -40,10 +40,10 @@ use self::wire::{
     ESTABLISHED_HEADER_SIZE, FLAG_CE, FLAG_KEY_EPOCH, FLAG_SP, build_encrypted,
     build_established_header, prepend_inner_header,
 };
-use crate::bloom::{BloomFilter, BloomState};
 use crate::cache::CoordCache;
 use crate::node::session::SessionEntry;
 use crate::peer::{ActivePeer, PeerConnection};
+use crate::proto::bloom::{BloomFilter, BloomState};
 use crate::proto::discovery::{Discovery, DiscoveryBackoff, DiscoveryForwardRateLimiter};
 use crate::proto::fmp::Fmp;
 use crate::proto::mmp::Mmp;

src/node/tests/bloom.rs

@@ -455,8 +455,8 @@ async fn test_bloom_filter_split_horizon() {
 /// counted once, not the double-count fingerprint.
 #[test]
 fn compute_mesh_size_counts_each_peer_filter_once() {
-    use crate::bloom::BloomFilter;
     use crate::peer::ActivePeer;
+    use crate::proto::bloom::BloomFilter;
     use crate::proto::stp::ParentDeclaration;
 
     let mut node = make_node();
@@ -550,8 +550,8 @@ fn compute_mesh_size_counts_each_peer_filter_once() {
 /// `estimated_mesh_size` carries.
 #[test]
 fn compute_mesh_size_unions_overlapping_filters() {
-    use crate::bloom::BloomFilter;
     use crate::peer::ActivePeer;
+    use crate::proto::bloom::BloomFilter;
 
     let mut node = make_node();
 
@@ -632,8 +632,8 @@ fn compute_mesh_size_unions_overlapping_filters() {
 /// removes the parent, and asserts the estimate does not collapse.
 #[test]
 fn compute_mesh_size_stable_across_parent_drop_with_cross_link() {
-    use crate::bloom::BloomFilter;
     use crate::peer::ActivePeer;
+    use crate::proto::bloom::BloomFilter;
 
     let mut node = make_node();
 

src/node/tests/bloom_poison.rs

@@ -7,9 +7,9 @@
 //! bloom.rs.
 
 use super::*;
-use crate::bloom::{BloomFilter, DEFAULT_FILTER_SIZE_BITS, DEFAULT_HASH_COUNT};
 use crate::peer::ActivePeer;
-use crate::protocol::FilterAnnounce;
+use crate::proto::bloom::FilterAnnounce;
+use crate::proto::bloom::{BloomFilter, DEFAULT_FILTER_SIZE_BITS, DEFAULT_HASH_COUNT};
 
 /// Inject a synthetic active peer into the node with a known NodeAddr.
 /// Returns the peer's NodeAddr.

src/node/tests/discovery.rs

@@ -1038,8 +1038,8 @@ async fn test_open_discovery_sweep_queues_eligible_skips_filtered() {
 /// that `initiate_lookup` ran fresh on each attempt.
 #[tokio::test]
 async fn test_check_pending_lookups_default_sequence_unreachable() {
-    use crate::bloom::BloomFilter;
     use crate::peer::ActivePeer;
+    use crate::proto::bloom::BloomFilter;
     use crate::proto::discovery::PendingLookup;
     use crate::transport::LinkId;
     use std::sync::mpsc;

src/node/tests/routing.rs

@@ -4,7 +4,7 @@
 //! filter priority, greedy tree routing, and tie-breaking.
 
 use super::*;
-use crate::bloom::BloomFilter;
+use crate::proto::bloom::BloomFilter;
 use crate::proto::stp::{ParentDeclaration, TreeCoordinate};
 use spanning_tree::{
     TestNode, cleanup_nodes, drain_all_packets, generate_random_edges, initiate_handshake,