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/library.properties

@@ -0,0 +1,10 @@
+name=microReticulum
+version=0.2.4
+author=Chad Attermann <attermann@gmail.com>
+maintainer=Chad Attermann <attermann@gmail.com>
+sentence=Port of Reticulum Network Stack to C++
+paragraph=Specifically but not exclusively targeting 32-bit and better MCUs
+category=Communication
+url=https://github.com/attermann/microReticulum.git
+architectures=*
+depends=ArduinoJson,MsgPack