v1.0.0: Boundary mode with bidirectional LoRa↔TCP transport

Vendor microReticulum library with boundary mode transport fixes:
- Two-whitelist system gates backbone traffic (local addresses +
  mentioned addresses from local devices)
- Allow control_hashes and local destinations through boundary filter
  (fixes backbone→LoRa path discovery)
- Fix get_cached_packet() to call unpack() instead of update_hash()
  (fixes empty destination_hash in path responses)
- LRPROOF Identity::recall null guard
- remaining_hops HEADER_1/BROADCAST fix for final-hop delivery
- PROOF packets excluded from boundary wrapping
- Iterator invalidation fix in transport table cleanup
- is_backbone flag replaces string matching for interface identification

Firmware changes:
- Set is_backbone(true) on backbone TCP interface
- Rename default TcpInterface name to BackboneInterface
- Update comments for dual-use TcpInterface (backbone + local AP)
- Use vendored lib/microReticulum instead of PlatformIO registry

lib/microReticulum/src/main.cpp

@@ -0,0 +1,23 @@
+// Only include if building locally and NOT testing
+#if defined(LIBRARY_TEST) && !defined(PIO_UNIT_TESTING)
+#include <stdio.h>
+
+#ifdef ARDUINO
+#include <Arduino.h>
+
+void setup() {
+	Serial.begin(115200);
+	Serial.print("\nSilly rabbit, microReticulum is a library!\n\nSee the examples directory for example programs that make use of this library.\n\n");
+}
+void loop() {
+}
+
+#else
+
+int main(void) {
+	printf("\nSilly rabbit, microReticulum is a library!\n\nSee the examples directory for example programs that make use of this library.\n\n");
+}
+
+#endif
+
+#endif