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/DEVELOPING.md

@@ -1,6 +1,6 @@
-# Being a Hush Developer
+# Being a DragonX Developer
 
-## Compiling Hush
+## Compiling DragonX
 
 Normal compiling is as simple as:
 
@@ -20,7 +20,7 @@ Divide how many GBs of RAM you have by 2, subtract one. Use that many jobs.
 ## Dealing with dependency changes
 
 Let's say you change a dependency and want the compile to notice. If your
-change is outside of the main Hush source code, in ./src, simply running
+change is outside of the main DragonX source code, in ./src, simply running
 `make` will not notice, and sometimes not even `build.sh`. You can always
 do a fresh clone or `make clean`, but that will take a lot of time. Those
 methods are actually best for Continuous Integration systems, but to help
@@ -54,14 +54,14 @@ If `make clean` produces a compilation error, you just experienced it.
 
 ## Switching branches
 
-Switching branches and doing partial compiles in Hush source code
+Switching branches and doing partial compiles in DragonX source code
 can introduce weird bugs, which are fixed by running `build.sh` again.
 Additionally, it's a good idea to run `make clean` before you switch
 between branches.
 
 ## Partial compiles
 
-At any point, you can modify hush source code and then use `make` or `build.sh`
+At any point, you can modify DragonX source code and then use `make` or `build.sh`
 to do a partial compile. The first is faster but the latter is more likely to
 work correctly in all circustances. Sometimes partial compiles break weird
 build system dependencies, and you must do a `make clean` first, or even
@@ -75,14 +75,14 @@ of a dependency or something inside of Rust, you will need `build.sh` .
 
 ## Generating new unix man pages
 
-Make sure that you have updated all version numbers in hushd and compiled, then
+Make sure that you have updated all version numbers in dragonxd and compiled, then
 to generate new unix man pages for that version :
 
 	./util/gen-manpages.sh
 
 ## Generating new debian packages
 
-After successfully compiling Hush, you can generate a debian package of these binaries with:
+After successfully compiling DragonX, you can generate a debian package of these binaries with:
 
 	./util/build-debian-package.sh
 
@@ -113,9 +113,8 @@ port) are ways to prevent them from communicating. This is good because these
 two HACs will eventually chain fork due to their different consensus rules and
 ban each other, wasting time, bandwidth and sanity.
 
-An example of doing this can be seen in the commit
-https://git.hush.is/hush/hush3/commit/d39503c13b7419620d138050899705ced557eef9
-which added the `-ac_burn` consensus changing option.
+An example of this pattern in the Git history is the commit which added the
+`-ac_burn` consensus changing option; search the log for `ac_burn` to find it.
 
 The chain magic value is the CRC32 checksum of every non-default consensus
 option the HAC uses.
@@ -128,4 +127,4 @@ modify `src/miner.cpp` to do whatever they want.
 
 If you think something else should be in this guide, please send your suggestions!
 
-Gitea: https://git.hush.is/hush/hush3
+Gitea: https://git.dragonx.is/DragonX/dragonx