* fix: raise UDP SO_RCVBUF on voice listeners (C-LOCAL)
Apply a 4 MB receive buffer on system and proxy UDP sockets to reduce
kernel RcvbufErrors under OBP load; size is configurable via GLOBAL.UDP_RCVBUF.
* fix: exclude byte-identical duplicates from HBP rate counter (A.2)
Check lastData before incrementing the ingress packet counter so compressed
duplicate bursts do not trigger legitimate RATE DROP on call start.
* fix: duplicate-safe TA embed phase and REPEAT VHEAD DMRA (B)
Ignore byte-identical B-E embed bursts so duplicate uplinks do not desync the
TA phase machine, and re-emit DMRA on every VHEAD on the REPEAT path.
* chore: document echo point-to-point and logged_in reconciliation (EN/ES)
Document multi-hotspot echo/service delivery via RX_PEER, the lst_seen
logged_in reconcile loop, and cross-links between user and dev guides.
Add a dedicated public page explaining routing, contention, timers,
SINGLE mode, static/dynamic TGs, silent activation, slot mapping and
OBP parity. Cross-link from behaviour-and-timers, bridges-and-talkgroups,
introduction and special-numbers, and register it in both mkdocs navs.
Document ADN-report-proxy so adn-server 2.x can feed v1 legacy monitors,
and sync EN/ES MkDocs with DATABASE, dynamic TGs, monitoring, and related topics.