feat(abacus-react): add dual publishing to npm and GitHub Packages

- Configure semantic-release for simultaneous publishing to both registries
- Update GitHub Actions workflow with dual authentication setup
- Add npm configuration for both registry.npmjs.org and npm.pkg.github.com
- Update package.json with correct repository URL and registry config
- Enhance documentation across README, CONTRIBUTING.md, and .claude/ files
- GitHub Packages uses GITHUB_TOKEN, npm requires NPM_TOKEN secret

This provides redundancy and choice for package consumers while maintaining
the same automatic semantic versioning workflow.

packages/abacus-react/.releaserc.json

@@ -45,6 +45,15 @@
         "npmPublish": true
       }
     ],
+    [
+      "@semantic-release/npm",
+      {
+        "npmPublish": true,
+        "pkgRoot": ".",
+        "tarballDir": "dist",
+        "registry": "https://npm.pkg.github.com"
+      }
+    ],
     [
       "@semantic-release/github",
       {

packages/abacus-react/README.md

@@ -16,6 +16,8 @@ A comprehensive React component for rendering interactive Soroban (Japanese abac
 
 ## Installation
 
+### From npm (recommended)
+
 ```bash
 npm install @soroban/abacus-react
 # or
@@ -24,6 +26,18 @@ pnpm add @soroban/abacus-react
 yarn add @soroban/abacus-react
 ```
 
+### From GitHub Packages
+
+```bash
+# Configure npm to use GitHub Packages for @soroban scope
+echo "@soroban:registry=https://npm.pkg.github.com" >> .npmrc
+
+# Then install
+npm install @soroban/abacus-react
+```
+
+The package is published to both npm and GitHub Packages simultaneously for redundancy and choice.
+
 ## Quick Start
 
 
@@ -404,8 +418,9 @@ BREAKING CHANGE: callback functions now receive different parameters
 ### Release Process
 
 1. **Automatic**: Releases happen automatically when changes are pushed to `main` branch
-2. **Manual testing**: Run `pnpm release:dry-run` to test release without publishing
-3. **Version tags**: Releases are tagged as `abacus-react-v1.2.3` (separate from monorepo versions)
+2. **Dual publishing**: Package is published to both npm and GitHub Packages simultaneously
+3. **Manual testing**: Run `pnpm release:dry-run` to test release without publishing
+4. **Version tags**: Releases are tagged as `abacus-react-v1.2.3` (separate from monorepo versions)
 
 ### Development Commands
 

packages/abacus-react/package.json

@@ -89,13 +89,14 @@
   "license": "MIT",
   "repository": {
     "type": "git",
-    "url": "https://github.com/soroban-flashcards/soroban-abacus-flashcards",
+    "url": "https://github.com/antialias/soroban-abacus-flashcards",
     "directory": "packages/abacus-react"
   },
   "engines": {
     "node": ">=18.0.0"
   },
   "publishConfig": {
-    "access": "public"
+    "access": "public",
+    "registry": "https://registry.npmjs.org"
   }
 }