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
