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()