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>

contrib/fresh_clone_compile_and_run.sh

@@ -11,19 +11,19 @@
 
 BRANCH=$1
 
-git clone https://git.hush.is/hush/hush3
-cd hush3
+git clone https://git.dragonx.is/DragonX/dragonx
+cd dragonx
 git checkout $BRANCH
 # You need 2GB of RAM per core, don't use too many
-# (GB of RAM)/2 - 1 is the optimal core count for compiling Hush
+# (GB of RAM)/2 - 1 is the optimal core count for compiling DragonX
 # `nproc` tells you how many cores you have
 JOBS=$2
 JOBZ=$(nproc) # if build.sh fails, we can use many more jobs with make
-# Want to fix this parrallel-only build system bug we inherited ? you are a new hush dev
+# Want to fix this parrallel-only build system bug we inherited ? you are a new DragonX dev
 # Sometimes the parrallel build fails because of a race condition, so
 # we do it a few times to Make Really Sure
 ./build.sh -j$JOBS;make -j$JOBZ;make -j$JOBZ;make -j$JOBZ
-./src/hushd &> hush.log &
-# You can give the entire or parts of this file to Hush developers for debugging,
+./src/dragonxd &> dragonx.log &
+# You can give the entire or parts of this file to DragonX developers for debugging,
 # but there is a lot of metadata!!! We don't want any more than we need to fix bugz
-tail -f hush.log
+tail -f dragonx.log