Rebrand hush3 to DragonX and share RandomX dataset across mining threads

Minimal rebrand (see compliant-rebrand branch for full rebrand):
- Rename binaries: hushd/hush-cli/hush-tx → dragonxd/dragonx-cli/dragonx-tx
- Default to DRAGONX chain params without -ac_* flags (randomx, blocktime=36, private=1)
- Update configure.ac: AC_INIT([DragonX],[1.0.0])
- Update client version string and user-agent to /DragonX:1.0.0/
- Add chainparams.cpp with DRAGONX network parameters
- Update build.sh, miner.cpp, pow.cpp for DragonX
- Add bootstrap-dragonx.sh utility script
- Update .gitignore for release directory

Share single RandomX dataset across all mining threads:
- Add RandomXDatasetManager with readers-writer lock, reducing RAM from
  ~2GB per thread to ~2GB total plus ~2MB per thread for the VM scratchpad
- Add LogProcessMemory() diagnostic helper for Linux and Windows

util/gen-linux-binary-release.sh

@@ -1,14 +1,15 @@
 #!/usr/bin/env bash
 # Copyright (c) 2016-2024 The Hush developers
+# Copyright (c) 2024-2026 The DragonX developers
 # Released under the GPLv3
 
 set -e
 set -x
 
-#hardcode and uncomment if hushd is not running on this machine
-#VERSION=3.6.3
-VERSION=$(./src/hushd --version|grep version|cut -d' ' -f4|cut -d- -f1|sed 's/v//g')
-DIR="hush-$VERSION-linux-amd64"
+#hardcode and uncomment if dragonxd is not running on this machine
+#VERSION=1.0.0
+VERSION=$(./src/dragonxd --version|grep version|cut -d' ' -f4|cut -d- -f1|sed 's/v//g')
+DIR="dragonx-$VERSION-linux-amd64"
 FILE="$DIR.tar"
 TIME=$(perl -e 'print time')
 
@@ -23,12 +24,13 @@ mkdir $BUILD
 echo "Created new build dir $BUILD"
 cp contrib/asmap/asmap.dat $BUILD
 cp sapling*.params $BUILD
+cp util/bootstrap-dragonx.sh $BUILD
 cd src
-cp hushd hush-cli hush-tx hush-arrakis-chain ../$BUILD
+cp dragonxd dragonx-cli dragonx-tx ../$BUILD
 cd ../$BUILD
-strip hushd hush-cli hush-tx
+strip dragonxd dragonx-cli dragonx-tx
 cd ..
-tar -f $FILE -c  hush-$VERSION-linux-amd64/*
+tar -f $FILE -c  dragonx-$VERSION-linux-amd64/*
 gzip -9 $FILE
 sha256sum *.gz
 du -sh *.gz