Fix LXMF bidirectional messaging, increase known_destinations cap

Outbound (Ratdeck→Python) was broken because Identity::recall() could
never find the recipient. Root cause: OS::time() returns seconds since
boot on ESP32, but persisted known_destinations entries carried timestamps
from the previous session. New announces got timestamp ~31s while persisted
entries had ~5000s, so the LRU cull immediately removed the new entry.

The microReticulum Identity.cpp fix (timestamp normalization on load) is
in .pio/libdeps and must be upstreamed to ratspeak/microReticulum separately.

Changes:
- known_destinations cap 256→512 (PSRAM pool was 1% used, plenty of room)
- Fix link delivery destHash: onLinkEstablished callback was passing link_id
  instead of LXMF destination hash, corrupting conversation routing
- Add diagnostic logging: [LXMF-DIAG], [TCP-DIAG], [HEART-DIAG], [DIAG-PROOF]
  for tracing link establishment, proof routing, and interface status

platformio.ini

@@ -24,7 +24,7 @@ build_flags =
     -DRNS_CONTAINER_ALLOCATOR=RNS_PSRAM_POOL_ALLOCATOR
     -DRNS_PSRAM_POOL_BUFFER_SIZE=2048000
     ; Raise microReticulum table caps — all containers go to 2MB PSRAM pool
-    -DRNS_KNOWN_DESTINATIONS_MAX=256
+    -DRNS_KNOWN_DESTINATIONS_MAX=512
     -DRNS_HASHLIST_MAX=256
     -DRNS_PATH_TABLE_MAX=256
     -DRNS_ANNOUNCE_TABLE_MAX=128

src/main.cpp

@@ -1055,6 +1055,15 @@ void loop() {
                           radioOnline ? "ON" : "OFF",
                           sdStore.isReady() ? "OK" : "FAIL",
                           flash.isReady() ? "OK" : "FAIL");
+            // Diagnostic: show registered transport interfaces and TCP connection status
+            {
+                auto& ifaces = RNS::Transport::get_interfaces();
+                int tcpUp = 0;
+                for (auto* tcp : tcpClients) { if (tcp && tcp->isConnected()) tcpUp++; }
+                Serial.printf("[HEART-DIAG] ifaces=%d tcp=%d/%d wifi=%s\n",
+                    (int)ifaces.size(), tcpUp, (int)tcpClients.size(),
+                    wifiSTAConnected ? "STA" : (wifiImpl ? "AP" : "OFF"));
+            }
             maxLoopTime = 0;
         }
     }

src/reticulum/LXMFManager.cpp

@@ -226,13 +226,22 @@ void LXMFManager::onOutLinkClosed(RNS::Link& link) {
 
 void LXMFManager::onLinkEstablished(RNS::Link& link) {
     if (!_instance) return;
+    Serial.printf("[LXMF-DIAG] onLinkEstablished fired! link_id=%s status=%d\n",
+        link.link_id().toHex().substr(0, 16).c_str(), (int)link.status());
     link.set_packet_callback([](const RNS::Bytes& data, const RNS::Packet& packet) {
         if (!_instance) return;
-        _instance->processIncoming(data.data(), data.size(), packet.destination_hash());
+        Serial.printf("[LXMF-DIAG] Link packet received! %d bytes pkt_dest=%s\n",
+            (int)data.size(), packet.destination_hash().toHex().substr(0, 16).c_str());
+        // Link delivery: data already contains [dest:16][src:16][sig:64][msgpack]
+        // Do NOT use packet.destination_hash() — that's the link_id, not the LXMF dest.
+        // Pass empty Bytes so processIncoming uses the destHash from unpackFull().
+        _instance->processIncoming(data.data(), data.size(), RNS::Bytes());
     });
 }
 
 void LXMFManager::processIncoming(const uint8_t* data, size_t len, const RNS::Bytes& destHash) {
+    Serial.printf("[LXMF-DIAG] processIncoming: %d bytes callerDestHash=%s\n",
+        (int)len, destHash.size() > 0 ? destHash.toHex().substr(0, 16).c_str() : "EMPTY(link)");
     LXMFMessage msg;
     if (!LXMFMessage::unpackFull(data, len, msg)) {
         Serial.printf("[LXMF] Failed to unpack incoming message (%d bytes)\n", (int)len);
@@ -240,6 +249,10 @@ void LXMFManager::processIncoming(const uint8_t* data, size_t len, const RNS::By
     }
     if (_rns && msg.sourceHash == _rns->destination().hash()) return;
 
+    Serial.printf("[LXMF-DIAG] unpackFull OK: src=%s dest=%s content_len=%d\n",
+        msg.sourceHash.toHex().substr(0, 8).c_str(),
+        msg.destHash.toHex().substr(0, 8).c_str(), (int)msg.content.size());
+
     // Deduplication: skip messages we've already processed
     std::string msgIdHex = msg.messageId.toHex();
     if (_seenMessageIds.count(msgIdHex)) {
@@ -252,7 +265,11 @@ void LXMFManager::processIncoming(const uint8_t* data, size_t len, const RNS::By
         _seenMessageIds.erase(_seenMessageIds.begin());
     }
 
-    msg.destHash = destHash;
+    // Only overwrite destHash if caller provided a real one (non-link delivery).
+    // For link delivery, unpackFull already parsed the correct destHash from the payload.
+    if (destHash.size() > 0) {
+        msg.destHash = destHash;
+    }
     Serial.printf("[LXMF] Message from %s (%d bytes) content_len=%d\n",
                   msg.sourceHash.toHex().substr(0, 8).c_str(), (int)len, (int)msg.content.size());
     if (_store) { _store->saveMessage(msg); }

src/transport/TCPClientInterface.cpp

@@ -138,6 +138,16 @@ void TCPClientInterface::send_outgoing(const RNS::Bytes& data) {
         uint8_t header_type = (flags >> 6) & 0x01;
         uint8_t packet_type = flags & 0x03;
 
+        // Diagnostic: identify packet types going through TCP
+        static const char* pt_names[] = {"DATA", "ANNOUNCE", "LINKREQ", "PROOF"};
+        Serial.printf("[TCP-DIAG] send: %d bytes ht=%d pt=%s(%d) to %s:%d\n",
+            (int)data.size(), header_type,
+            (packet_type < 4) ? pt_names[packet_type] : "?", packet_type,
+            _host.c_str(), _port);
+        if (packet_type == 0x03) {
+            Serial.printf("[TCP-DIAG] *** PROOF packet being sent via TCP! ***\n");
+        }
+
         if (packet_type != 0x01) {  // Not ANNOUNCE
             if (header_type == 0) {
                 // Header1 → wrap as Header2 (handles hops==1, hops==0, unknown path)