fix(mesh): Reticulum resource transfers actually deliver — 4 root causes

E2E-verified both directions dev-box<->x250 over real RF (5KB image ~60s):

1. Sender daemon never called link.identify() — receiver's
   get_remote_identity() was None, so every arrived transfer carried an
   empty source_hash and the Rust side dropped it (now also warns
   instead of silently vanishing it).
2. Receiver treated resource.data as bytes, but RNS hands a concluded
   Resource's data as a file-like BufferedReader — b64encode raised
   TypeError and the transfer was lost even when attributed.
3. Radio twins of merged contacts carry the peer's Archipelago ed25519
   key as pubkey_hex, not an RNS hash — prefix lookup could never match
   ('Unknown Reticulum prefix', observed live). resolve_dest_hash now
   falls back to matching the announce-bound arch_pubkey_hex.
4. The daemon RPC socket kept asyncio's default 64KiB line limit; any
   attachment >~48KB overflowed it and tore down the whole daemon
   connection ('reticulum-daemon is gone'). Raised to 16MiB.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

core/archipelago/src/mesh/reticulum.rs

@@ -525,6 +525,28 @@ impl ReticulumLink {
         info!(count = self.peers.len(), "Loaded persisted Reticulum peers");
     }
 
+    /// Resolve a caller-supplied 6-byte routing prefix to a full 16-byte RNS
+    /// destination hash. Two shapes arrive here depending on how the contact
+    /// record was born (observed live 2026-07-28, image-to-merged-contact):
+    ///   1. the peer's RNS dest-hash prefix (contacts created from an RNS
+    ///      announce) — direct `prefix_to_hash` hit;
+    ///   2. the peer's Archipelago ed25519 pubkey prefix (radio twins bound
+    ///      via the ARCHY announce blob store the arch key as `pubkey_hex`) —
+    ///      no dest-hash match possible, so fall back to scanning peers whose
+    ///      announce-bound `arch_pubkey_hex` starts with the prefix.
+    fn resolve_dest_hash(&self, prefix: &[u8; 6]) -> Option<[u8; 16]> {
+        if let Some(hash) = self.prefix_to_hash.get(prefix) {
+            return Some(*hash);
+        }
+        let hex_prefix = hex::encode(prefix);
+        self.peers.values().find_map(|p| {
+            p.arch_pubkey_hex
+                .as_deref()
+                .filter(|arch| arch.starts_with(&hex_prefix))
+                .map(|_| p.dest_hash)
+        })
+    }
+
     /// Best-effort sync write of the current peer table — called after any
     /// insert that adds/renames a peer. Infrequent (announces/first-contact,
     /// not per-message) so a blocking write here is a fine trade for keeping
@@ -601,11 +623,7 @@ impl ReticulumLink {
         dest_pubkey_prefix: &[u8; 6],
         payload: &[u8],
     ) -> Result<()> {
-        let dest_hash = self
+        let dest_hash = self.resolve_dest_hash(dest_pubkey_prefix).with_context(|| {
-            .prefix_to_hash
-            .get(dest_pubkey_prefix)
-            .copied()
-            .with_context(|| {
             format!(
                 "Unknown Reticulum prefix {} — peer hasn't announced yet",
                 hex::encode(dest_pubkey_prefix)
@@ -645,11 +663,7 @@ impl ReticulumLink {
         caption: Option<&str>,
     ) -> Result<()> {
         use base64::{engine::general_purpose::STANDARD as B64, Engine as _};
-        let dest_hash = self
+        let dest_hash = self.resolve_dest_hash(dest_pubkey_prefix).with_context(|| {
-            .prefix_to_hash
-            .get(dest_pubkey_prefix)
-            .copied()
-            .with_context(|| {
             format!(
                 "Unknown Reticulum prefix {} — peer hasn't announced yet",
                 hex::encode(dest_pubkey_prefix)
@@ -677,11 +691,7 @@ impl ReticulumLink {
     /// `handle_event`, not awaited here.
     pub async fn send_resource(&mut self, dest_pubkey_prefix: &[u8; 6], data: &[u8]) -> Result<()> {
         use base64::{engine::general_purpose::STANDARD as B64, Engine as _};
-        let dest_hash = self
+        let dest_hash = self.resolve_dest_hash(dest_pubkey_prefix).with_context(|| {
-            .prefix_to_hash
-            .get(dest_pubkey_prefix)
-            .copied()
-            .with_context(|| {
             format!(
                 "Unknown Reticulum prefix {} — peer hasn't announced yet",
                 hex::encode(dest_pubkey_prefix)
@@ -1023,10 +1033,19 @@ impl ReticulumLink {
                     .push_back(build_synthetic_frame(&prefix, &content));
             }
             Some("resource_recv") => {
-                let Some(source_hex) = ev.get("source_hash").and_then(Value::as_str) else {
+                let source_hex = ev
-                    return;
+                    .get("source_hash")
-                };
+                    .and_then(Value::as_str)
+                    .unwrap_or_default();
                 let Ok(source_hash) = parse_hash16(source_hex) else {
+                    // An empty source_hash means the sender's link wasn't
+                    // identified (pre-identify daemon build on the far end) —
+                    // the blob is undeliverable without attribution, but say
+                    // so instead of vanishing it.
+                    warn!(
+                        source = source_hex,
+                        "Dropping inbound Reticulum resource without valid source identity"
+                    );
                     return;
                 };
                 let prefix: [u8; 6] = source_hash[..6].try_into().unwrap();

reticulum-daemon/reticulum_daemon.py

@@ -437,13 +437,29 @@ class ReticulumDaemon:
             identity, RNS.Destination.OUT, RNS.Destination.SINGLE,
             "archy", "resource",
         )
-        link = RNS.Link(out_dest)
+        # established_callback identifies us to the peer BEFORE any Resource
+        # goes out: the receiving daemon attributes an inbound resource via
+        # link.get_remote_identity() (see _on_resource_received), which is
+        # None unless the initiator calls identify() — without this every
+        # transfer arrives with an empty source_hash and the Rust side can't
+        # route it to a contact (observed live 2026-07-28: 5KB image sent,
+        # concluded COMPLETE, never surfaced on the receiving node).
+        link = RNS.Link(
+            out_dest,
+            established_callback=lambda lk: self._on_out_link_established(
+                resource_hash, lk
+            ),
+        )
         link.set_link_closed_callback(
             lambda lk: self.links.pop(resource_hash, None)
         )
         self.links[resource_hash] = link
         return link, resource_hash
 
+    def _on_out_link_established(self, resource_hash: bytes, link):
+        link.identify(self.identity)
+        self._flush_pending_resource_sends(resource_hash, link)
+
     def _send_resource(self, req: dict):
         import RNS
         req_id = req.get("id", "")
@@ -463,14 +479,14 @@ class ReticulumDaemon:
         if link.status == RNS.Link.ACTIVE:
             self._start_resource(link, data, req_id)
         else:
-            # Link is establishing — queue and flush from the established
+            # Link is establishing — queue; the creation-time established
-            # callback. set_link_established_callback only fires once per Link
+            # callback (_on_out_link_established) identifies us then flushes
-            # object (the cache is reused across sends), so re-set it here to
+            # the queue. Re-check afterwards to close the race where the
-            # make sure THIS send's queue entry gets flushed too.
+            # link went ACTIVE between the status check and the append
+            # (the callback fires once, on the RNS thread).
             self.pending_resource_sends[resource_hash].append((data, req_id))
-            link.set_link_established_callback(
+            if link.status == RNS.Link.ACTIVE:
-                lambda lk: self._flush_pending_resource_sends(resource_hash, lk)
+                self._flush_pending_resource_sends(resource_hash, link)
-            )
 
     def _flush_pending_resource_sends(self, resource_hash: bytes, link):
         import RNS
@@ -518,10 +534,17 @@ class ReticulumDaemon:
                 RNS.Destination.hash(identity, "lxmf", "delivery").hex()
                 if identity is not None else ""
             )
+            # RNS hands a concluded Resource's data as a file-like object
+            # (BufferedReader over the assembled stream), not bytes —
+            # observed live 2026-07-28: b64encode raised "a bytes-like
+            # object is required" and every received transfer was lost.
+            data = resource.data
+            if hasattr(data, "read"):
+                data = data.read()
             self._emit_threadsafe({
                 "event": "resource_recv",
                 "source_hash": source_hash,
-                "data_b64": base64.b64encode(resource.data).decode("ascii"),
+                "data_b64": base64.b64encode(data).decode("ascii"),
             })
         except Exception as e:  # never let a callback kill the RNS thread
             self._emit_threadsafe({"event": "error", "where": "resource_recv",
@@ -531,7 +554,14 @@ class ReticulumDaemon:
         sock_path = self.args.socket
         if os.path.exists(sock_path):
             os.unlink(sock_path)
-        server = await asyncio.start_unix_server(self._handle_client, path=sock_path)
+        # limit: asyncio's default per-line StreamReader cap is 64KiB, but
+        # send_resource requests carry the whole payload base64-encoded on one
+        # JSON line — a ~48KB+ attachment overflows the default and the raised
+        # LimitOverrunError tears down the RPC connection (the Rust side then
+        # sees "reticulum-daemon is gone" and restarts the whole session).
+        server = await asyncio.start_unix_server(
+            self._handle_client, path=sock_path, limit=16 * 1024 * 1024
+        )
         os.chmod(sock_path, 0o600)
         self.announce()
         async with server: