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>

doc/help.md

@@ -17,10 +17,9 @@ where this data lives on your computer and then move some files around, then res
 
 ### On Linux
 
-If you are on Linux, your wallet lives at `~/.hush/HUSH3/wallet.dat` or if you have a really old
-legacy wallet it could be at `~/.komodo/HUSH3/wallet.dat` . We will assume the first location.
+If you are on Linux, your wallet lives at `~/.hush/DRAGONX/wallet.dat`.
 
-What we will do is backup your entire `HUSH3` directory, including the blockchain data and wallet,
+What we will do is backup your entire `DRAGONX` directory, including the blockchain data and wallet,
 then copy the wallet from there into a new directory. This is a non-destructive process that creates
 a new backup of your wallet.
 
@@ -28,25 +27,26 @@ a new backup of your wallet.
 # Make sure your node is not running before doing any of this!
 # Doing this while your node is running could corrupt your wallet.dat
 cd ~/.hush
-mv HUSH3 HUSH3-backup                       # backup all data
-mkdir HUSH3                                 # make a new dir
-cp HUSH3-backup/wallet.dat HUSH3/wallet.dat # copy old wallet to new dir
+mv DRAGONX DRAGONX-backup                          # backup all data
+mkdir DRAGONX                                      # make a new dir
+cp DRAGONX-backup/wallet.dat DRAGONX/wallet.dat    # copy old wallet to new dir
 ```
 
-At this point if you are GUI user using SilentDragon, you can restart the GUI wallet
-and it should perform a fresh sync with your wallet. This will likely take at least
-a few hours or much longer depending on your internet connection.
+At this point restart your node (`dragonxd`) and it will perform a fresh sync using your
+wallet. This will likely take at least a few hours or much longer depending on your
+internet connection.
 
 ### On Windows
 
-Basically you want to find where your Hush wallet is, move the directory that contains
+Basically you want to find where your DragonX wallet is, move the directory that contains
 that wallet.dat file to a new name, then create that same directory and then copy wallet.dat into it.
-Different versions of Windows store things in different locations.
+Different versions of Windows store things in different locations. Note the app-data folder is
+named `Hush` (inherited) with a `DRAGONX` subdirectory.
 
-For example your wallet might be in `C:\Users\Admin\AppData\Roaming\Hush\HUSH3\wallet.dat` . 
+For example your wallet might be in `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX\wallet.dat` .
 That means you need to
 
-    * Rename the directory `C:\Users\Admin\AppData\Roaming\Hush\HUSH3` to something like `C:\Users\Admin\AppData\Roaming\Hush\HUSH3-backup`
-    * Create a new directory called `C:\Users\Admin\AppData\Roaming\Hush\HUSH3`
-    * Copy the file `C:\Users\Admin\AppData\Roaming\Hush\HUSH3-backup\wallet.dat` to `C:\Users\Admin\AppData\Roaming\Hush\HUSH3`
-    * Now start the SilentDragon GUI wallet
+    * Rename the directory `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX` to something like `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX-backup`
+    * Create a new directory called `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX`
+    * Copy the file `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX-backup\wallet.dat` to `C:\Users\Admin\AppData\Roaming\Hush\DRAGONX`
+    * Now start your DragonX node again