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/CONTRIBUTING.md

@@ -1,7 +1,7 @@
 
-# Hush Core (hushd) Software Contribution Guidelines
+# DragonX Core (dragonxd) Software Contribution Guidelines
 
-Thank you for reaching out and trying to make Hush an even better software application and cryptocoin platform. These contribution guidelines shall help you figuring out where you can be helpful and how to easily get started.
+Thank you for reaching out and trying to make DragonX an even better software application and cryptocoin platform. These contribution guidelines shall help you figuring out where you can be helpful and how to easily get started.
 
 ## Table of Contents
 
@@ -14,15 +14,13 @@ Thank you for reaching out and trying to make Hush an even better software appli
 0. [Community](#community)
 
 ## Types of contributions we're looking for
-There are many ways you can directly contribute to Hush:
+There are many ways you can directly contribute to DragonX:
 
-* Debug and test the Hush Core code
+* Debug and test the DragonX Core code
 * Find and fix bugs
 * Improve suboptimal code
 * Extend our software
-* Perform a secure code review of Hush Full Node and other Hush-related software
-
-We have a curated list of projects with details about difficulty level and languages involved: https://git.hush.is/hush/projects
+* Perform a secure code review of DragonX Full Node and other DragonX-related software
 
 Interested in making a contribution? Read on!
 
@@ -31,15 +29,14 @@ Interested in making a contribution? Read on!
 Before we get started, here are a few things we expect from you (and that you should expect from others):
 
 * Be kind and thoughtful in your conversations around this project. We all come from different backgrounds and projects, which means we likely have different perspectives on "how free software and open source is done." Try to listen to others rather than convince them that your way is correct.
-* Open Source Guides are released with a [Contributor Code of Conduct](./code_of_conduct.md). By participating in this project, you agree to abide by its terms.
 * If you open a pull request, please ensure that your contribution does not increase test failures. If there are additional test failures, you will need to address them before we can merge your contribution.
 * When adding content, please consider if it is widely valuable. Please don't add references or links to things you or your employer have created as others will do so if they appreciate it.
 
 ## How to contribute
 
-If you'd like to contribute, start by searching through the [issues](https://git.hush.is/hush/hush3/issues) and [pull requests](https://git.hush.is/hush/hush3/pulls) to see whether someone else has raised a similar idea or question.
+If you'd like to contribute, start by searching through the [issues](https://git.dragonx.is/DragonX/dragonx/issues) and [pull requests](https://git.dragonx.is/DragonX/dragonx/pulls) to see whether someone else has raised a similar idea or question.
 
-If you don't see your idea listed, and you think it can contribute to Hush, do one of the following:
+If you don't see your idea listed, and you think it can contribute to DragonX, do one of the following:
 * **If your contribution is minor,** such as a fixing a typo, open a pull request.
 * **If your contribution is major,** such as a new feature or bugfix, start by opening an issue first. That way, other contributors can weigh in on the discussion before you do any work.
 
@@ -49,9 +46,9 @@ Don't write shitty code. Do not emulate "jl777 code style" from Komodo, we consi
 
 ## Setting up your environment
 
-The Hush Core (hushd) is mainly written in C++ with specific modules written in C. Follow the [Install](https://git.hush.is/hush/hush3/src/branch/master/INSTALL.md) instructions to build hushd from sources. For more informations about the Hush Platform and a full API documentation please visit the official [Hush Developer documentation](https://faq.hush.is/rpc/)
+DragonX Core (dragonxd) is mainly written in C++ with specific modules written in C. See the build instructions in the [README](../README.md) to build dragonxd from sources.
 
-Other Hush software is written in Rust or Go. We avoid Javascript at all costs.
+Other DragonX software is written in Rust or Go. We avoid Javascript at all costs.
 
 ## Contribution review process