docs: rebrand documentation, packaging, and helper scripts to DragonX

The docs/packaging were largely un-rebranded Hush3 content, with several
docs stating facts that are wrong for DragonX. This rewrites them against
the verified DragonX source state.

Corrections (not just branding):
- PoW: RandomX (CPU), not Equihash/ASIC — README, overview.md, randomx.md
- Privacy: private from genesis (ac_private=1, Sapling@height1), not "as of
  block 340000" — overview.md, payment-api.md
- Removed the false "coinbase must be shielded" consensus claim
  (shield-coinbase.md, payment-api.md); coinbase is directly spendable
- Fixed default fee 0.0001 (was 0.0010000, 10x); stratum port 22769 (was 19031)
- datadir ~/.hush/DRAGONX, DRAGONX.conf, dragonxd/dragonx-cli/dragonx-tx,
  git.dragonx.is throughout; branch model dev->dragonx
- Softened the inherited dPoW reorg claim (no live DragonX notary infra)

Packaging: fix build-debian-package.sh + gen-manpages.sh to use the dragonx
binaries/manpages; rename bash-completions to dragonx*; drop hush-arrakis-chain
from the package. Keep /usr/share/hush (hardcoded in the binary for params).

Also: README links/logo, ObsidianDragon + SilentDragonXAndroid wallets,
networking/init/dev-process/contrib/util rebrand, and leftover helper scripts.
Delete legacy duplicates (hushd.* init/service, HUSH3.conf examples,
OLD_WALLETS.md, hsc.md) and rename hush-uri.bat -> dragonx-uri.bat.

Out of scope (noted, not changed): historical changelog/copyright, the Hush
mainnet airdrop snapshot, seed data files, depends/ source mirrors, and the
in-code strCurrencyUnits="HUSH".

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

util/build-arm-xcompile.sh

@@ -3,8 +3,8 @@
 # Distributed under the GPLv3 software license, see the accompanying
 # file COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html
 
-# For use with https://git.hush.is/jahway603/hush-docs/src/branch/master/advanced/cross-compile-hush-full-node-to-aarch64-with-docker.md,
-# Please follow that
+# Cross-compiles a DragonX full node to aarch64 (ARM) using an aarch64 GCC toolchain.
+# Intended to be run inside a Docker builder with the aarch64-linux-gnu cross toolchain installed.
 set -eu -o pipefail
 
 # Check if cmake, a new dependency for randomx support, is installed on system and exits if it is not
@@ -21,12 +21,12 @@ function cmd_pref() {
     fi
 }
 cat <<'EOF'
- .~~~~~~~~~~~~~~~~.
-{{ Building Hush!! }}
- `~~~~~~~~~~~~~~~~`
+ .~~~~~~~~~~~~~~~~~~~.
+{{ Building DragonX!! }}
+ `~~~~~~~~~~~~~~~~~~~`
         \   ^__^
-         \  (@@)\_______            
-            (__)\ HUSH  )\/\      $
+         \  (@@)\_______
+            (__)\DRAGONX)\/\      $
     z        zz ||----w |      z  |
 zz  zz  z       || z   ||xxx   z z|z zz
 zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
@@ -65,15 +65,15 @@ if [ "x$*" = 'x--help' ]
 then
     cat ./util/dragon.txt
     cat <<EOF
-Welcome To The Hush Build System, Here Be Dragons!
+Welcome To The DragonX Build System, Here Be Dragons!
 Usage:
 $0 --help
   Show this help message and exit.
 $0 [ --enable-lcov || --disable-tests ] [ --disable-mining ] [ --disable-libs ] [ MAKEARGS... ]
-  Build Hush and most of its transitive dependencies from source. MAKEARGS are applied to both dependencies and Hush itself.
-  If --enable-lcov is passed, Hush is configured to add coverage instrumentation, thus enabling "make cov" to work.
-  If --disable-tests is passed instead, the Hush tests are not built.
-  If --disable-mining is passed, Hush is configured to not build any mining code. It must be passed after the test arguments, if present.
+  Build DragonX and most of its transitive dependencies from source. MAKEARGS are applied to both dependencies and DragonX itself.
+  If --enable-lcov is passed, DragonX is configured to add coverage instrumentation, thus enabling "make cov" to work.
+  If --disable-tests is passed instead, the DragonX tests are not built.
+  If --disable-mining is passed, DragonX is configured to not build any mining code. It must be passed after the test arguments, if present.
   It must be passed after the test/mining arguments, if present.
 EOF
     exit 0