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/overview.md

@@ -1,25 +1,31 @@
-# Hush Overview
+# DragonX Overview
 
 ## Mining Algorithm
 
-Equihash (200,9) (ASIC)
+RandomX (CPU). DragonX is CPU-mineable using the RandomX Proof-of-Work algorithm
+(the same family used by Monero). ASIC and GPU mining are not applicable. See
+[randomx.md](randomx.md) for details.
 
 ## Block time
 
-75 seconds
+36 seconds
+
+## Block reward
+
+3 DRAGONX per block, halving every 3,500,000 blocks.
 
 ## Block size
 
-4MB
+4 MB (consensus maximum)
 
 ## P2P
 
-TLS1.3 via WolfSSL is enforced for all network connections as of v3.6.1 .
-Many ciphersuites are technically supported by TLS1.3 but many of them
-are ancient, proved to be less secure than intended or likely backdoored.
-Hush only uses what are widely considered to be the most secure and [best ciphersuites](https://ciphersuite.info/cs/).
+TLS1.3 via WolfSSL is enforced for all network connections. Many ciphersuites are
+technically supported by TLS1.3 but many of them are ancient, proved to be less secure
+than intended or likely backdoored. DragonX only uses what are widely considered to be the
+most secure and [best ciphersuites](https://ciphersuite.info/cs/).
 
-New Hush P2P connections randomly choose between these two ciphersuites each
+New DragonX P2P connections randomly choose between these two ciphersuites each
 time a new connection to a peer is created:
 
   * `TLS_AES_256_GCM_SHA384`
@@ -35,10 +41,18 @@ IP address owns which addresses.
 
 ## RPC
 
-Inherited many RPC's from Bitcoin and Zcash with many new ones
+Inherited many RPCs from Bitcoin and Zcash, with many new ones.
 
 ## Consensus
 
-Hush is a mandatory privacy blockchain as of Block 340000 (Nov 2020),
-which means you can only send to a shielded address, never to a transparent
-address. This is enforced via consensus rules and sometimes called "z2z".
+DragonX is a fully private blockchain from genesis. The consensus parameter
+`ac_private=1` is active from block 1 and Sapling is active at height 1, so every
+non-coinbase output must be shielded — you can only send to a shielded (`zs...`)
+address, never to a transparent address. This is sometimes called "z2z". Unlike
+chains that switched on mandatory privacy at a later height, DragonX enforces it
+from the very first block.
+
+Transparent addresses exist only to receive mining coinbase; mature coinbase is
+directly spendable and is not required to be shielded first (shielding it with
+`z_shieldcoinbase` is an optional privacy step). See
+[hd-transparent-keys.md](hd-transparent-keys.md).