Integration 2026 week 15

* !4014 Microamp FR2 configuration file and documentation
* !4029 nr rlc: tolerate bogus data
* !4032 build_oai fixes: harmonize duplicate options, remove wrong --build-lib handling
* !3977 Further unused arguments cleanup
* !4009 Fix for NULL pucch-ResourceCommon at MSG4
* !4037 Increase reliability of ltebox start
* !4034 Prevent infinite loop on Single Entry PHR handling
* !4038 doc(record_db): explain how to use record_db
* fix compilation of T tracers with 'make'
* !3489 Thread-pool support for TX symbol processing.