WHATSNEW: document how to select RLC AM; cover the last three commits

Adds a "Selecting RLC AM" section: now that AM actually works on both RATs,
say how to turn it on. Without SDAP it is Ip2Nic's per-traffic-class
conversationalRlc/streamingRlc/interactiveRlc/backgroundRlc parameters (all
still defaulting to "UM", so nothing changes for existing simulations); with
SDAP it is the per-DRB rlcType field of NrSdap.drbConfig. Both ends of a
bearer must be configured alike -- each node builds its entity from its own
configuration, and nothing cross-checks the mode.

Also documents the three doc/cosmetics commits since the last WHATSNEW
update (entity doc comments retargeted at the compounds, file headers,
@Class removal, IRlcAmEntities.ned split), corrects a stale "rlc*" to
"lteRlc*", and dates the release 2026-07-31.

Author: avarga

WHATSNEW.md

@@ -1,6 +1,6 @@
 # What's New in Simu5G
 
-## v1.6.0 (2026-07-28)
+## v1.6.0 (2026-07-31)
 
 This release adds a standards-compliant NR RLC to Simu5G. RLC Unacknowledged
 Mode and Acknowledged Mode per TS 38.322 -- contributed by Esteban Egea Lopez
@@ -36,7 +36,7 @@ it as well. This release adds a faithful NR RLC:
   `nrRlcUmEntityModuleType` and `nrRlcAmEntityModuleType` parameters (default:
   the new `NrRlcUmEntity`/`NrRlcAmEntity` compound modules), and selects them
   for every bearer that has an NR node at either end; LTE bearers keep the
-  `rlc*` compounds. RLC framing is a function of the RAT rather than a free
+  `lteRlc*` ones. RLC framing is a function of the RAT rather than a free
   choice, so there is no LTE/NR mix; TM, being transparent, is identical for
   both RATs and has no NR variant.
 
@@ -105,11 +105,48 @@ LTE-specific:
   `maxRtxThreshold` retransmissions, wired to the same
   `BearerManagement` teardown and RRC re-establishment as the NR AM.
 
-RLC AM is selected per traffic class with the `conversationalRlc`,
-`streamingRlc`, `interactiveRlc` and `backgroundRlc` parameters of `Ip2Nic`.
 Since no configuration could use the old LTE AM, this does not affect existing
 simulation results.
 
+### Selecting RLC AM
+
+Acknowledged Mode is now usable on both RATs -- previously there was no NR AM
+implementation at all, and an NR bearer asking for AM got the LTE one, which did
+not work -- but nothing selects it by default: every bearer stays in the mode it
+had before, so existing simulations are unaffected. Two mechanisms choose the
+mode of a bearer, depending on whether SDAP is in the stack.
+
+Without SDAP, `Ip2Nic` classifies each packet into a traffic class by packet name
+(`VoIP*` -> conversational, `gaming*` -> interactive, `VoDPacket*` -> streaming,
+anything else -> background) and maps the class to an RLC mode with its
+`conversationalRlc`, `streamingRlc`, `interactiveRlc` and `backgroundRlc`
+parameters. They accept `"TM"`, `"UM"` and `"AM"`, and all four default to
+`"UM"` -- which is the pre-v1.6.0 behavior, kept for backward compatibility:
+
+      **.cellularNic.ip2nic.conversationalRlc = "AM"
+
+With SDAP in the stack (`hasSdap = true` on the NR NIC, which propagates into
+`ip2nic.hasSdap`), `Ip2Nic` skips traffic classification entirely and the mode
+becomes a property of the DRB: every entry of `NrSdap.drbConfig` takes an
+optional `rlcType` field, again one of `"AM"`, `"UM"` and `"TM"`, and again
+defaulting to `"UM"`:
+
+      *.gnb.cellularNic.hasSdap = true
+      *.gnb.cellularNic.sdap.drbConfig = [
+          {"drb": 0, "ue": 2049, "qfiList": [1, 2], "rlcType": "UM"},
+          {"drb": 1, "ue": 2049, "qfiList": [3, 4], "rlcType": "AM"}]
+
+Either way, both ends of a bearer must be configured with the same mode: each
+node builds its own RLC entity from its own configuration, so a mismatch leaves
+an AM entity facing a UM one. The `**.` wildcard above takes care of that for
+`Ip2Nic`; with SDAP, the UE's `drbConfig` entry for a DRB and the gNB's entry
+for the same DRB have to agree on `rlcType`.
+
+Which entity type then implements the mode follows from the RAT, as described
+above: an AM bearer with an NR node at either end runs the `NrRlcAmEntity`
+compound, an LTE one `LteRlcAmEntity`. TM is available on both, and is the same
+entity for both.
+
 ### RLC validation scenarios
 
 The new `simulations/nr/rlc` and `simulations/lte/rlc` directories hold
@@ -261,6 +298,21 @@ bearer individually measurable.
   `lte/test_handover` (157 configurations in total), and the rows were
   re-recorded for the NR RLC default and the statistics changes.
 
+- **Documentation**: the RLC entity documentation comments were retargeted at
+  the compound modules that actually bind them -- several still referred to
+  per-side `rlcUm{Tx,Rx}EntityModuleType` parameters, which v1.5.1 replaced
+  with selection on the per-bearer compound -- and the `RlcUmEntityBase` /
+  `RlcAmEntityBase` comments now name both of their concrete subclasses.
+
+- **Source housekeeping**: file headers were brought in line -- the contributed
+  NR RLC sources now carry the standard Simu5G header naming their author
+  instead of an LGPL blurb, files that had no header got one, and new files
+  that had inherited the header of the file they were derived from now name
+  their actual author. The redundant `@class` line was dropped from the C++
+  class comments, and `IRlcAmEntities.ned` was split into `IRlcAmTxEntity.ned`
+  and `IRlcAmRxEntity.ned`, one interface per file. The interfaces themselves,
+  and all type names, are unchanged.
+
 ## v1.5.2 (2026-07-30)
 
 This release corrects the names of the per-bearer PDCP and RLC entity modules