Update Cachix cache name to mikkihugo

Use the actual Cachix cache name 'mikkihugo' throughout all
configuration files and workflows.

Changed:
- flake.nix: mikkihugo.cachix.org
- cachix.nix: name = mikkihugo
- nix-ci.yml: name: mikkihugo
- cachix-push.yml: name: mikkihugo
- NIX_CACHING.md: updated documentation

Cache URL: https://mikkihugo.cachix.org
Dashboard: https://app.cachix.org/cache/mikkihugo

Users can now use:
  cachix use mikkihugo
  nix develop  # automatically pulls from mikkihugo cache

Author: claude

.github/NIX_CACHING.md

@@ -8,7 +8,7 @@ The flake automatically tries caches in order:
 1. **cache.nixos.org** (official, always first)
 2. **nix-community.cachix.org** (community cache, high hit rate)
 3. **cache.garnix.io** (Garnix CI cache, automatic builds)
-4. **singularity-ng.cachix.org** (our cache)
+4. **mikkihugo.cachix.org** (our cache)
 5. **Magic Nix Cache** (GitHub Actions only)
 
 All caches are **FREE** and configured automatically!
@@ -130,8 +130,8 @@ The flake includes Cachix configuration:
 
 ```nix
 nixConfig = {
-  extra-substituters = [ "https://singularity-ng.cachix.org" ];
-  extra-trusted-public-keys = [ "singularity-ng.cachix.org-1:key" ];
+  extra-substituters = [ "https://mikkihugo.cachix.org" ];
+  extra-trusted-public-keys = [ "mikkihugo.cachix.org-1:key" ];
 };
 ```
 

.github/workflows/cachix-push.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Setup Cachix
         uses: cachix/cachix-action@v15
         with:
-          name: singularity-ng
+          name: mikkihugo
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
           pushFilter: '(-source$|\.drv$)'
 
@@ -61,5 +61,5 @@ jobs:
           echo "    cachix use singularity-ng"
           echo ""
           echo "Or add to /etc/nix/nix.conf:"
-          echo "    substituters = https://cache.nixos.org https://singularity-ng.cachix.org"
-          echo "    trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= singularity-ng.cachix.org-1:your-key-here"
+          echo "    substituters = https://cache.nixos.org https://mikkihugo.cachix.org"
+          echo "    trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= mikkihugo.cachix.org-1:your-key-here"

.github/workflows/nix-ci.yml

@@ -31,13 +31,13 @@ jobs:
           extra-conf: |
             experimental-features = nix-command flakes
             # Multiple free Nix caches for maximum hit rate
-            substituters = https://cache.nixos.org https://nix-community.cachix.org https://cache.garnix.io https://singularity-ng.cachix.org
-            trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs= cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g= singularity-ng.cachix.org-1:your-key-here
+            substituters = https://cache.nixos.org https://nix-community.cachix.org https://cache.garnix.io https://mikkihugo.cachix.org
+            trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs= cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g= mikkihugo.cachix.org-1:your-key-here
 
       - name: Setup Cachix (org cache)
         uses: cachix/cachix-action@v15
         with:
-          name: singularity-ng
+          name: mikkihugo
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
           skipPush: false
 

cachix.nix

@@ -28,13 +28,13 @@
 
     # Option 2: Manual nix.conf configuration
     # Add to /etc/nix/nix.conf or ~/.config/nix/nix.conf:
-    substituters = https://cache.nixos.org https://singularity-ng.cachix.org
-    trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= singularity-ng.cachix.org-1:your-signing-key-here
+    substituters = https://cache.nixos.org https://mikkihugo.cachix.org
+    trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= mikkihugo.cachix.org-1:your-signing-key-here
 
     # Option 3: In your flake.nix
     nixConfig = {
-      extra-substituters = [ "https://singularity-ng.cachix.org" ];
-      extra-trusted-public-keys = [ "singularity-ng.cachix.org-1:your-signing-key-here" ];
+      extra-substituters = [ "https://mikkihugo.cachix.org" ];
+      extra-trusted-public-keys = [ "mikkihugo.cachix.org-1:your-signing-key-here" ];
     };
   '';
 }

flake.nix

@@ -8,14 +8,14 @@
       "https://nix-community.cachix.org"
       "https://cache.garnix.io"
       # Organization cache
-      "https://singularity-ng.cachix.org"
+      "https://mikkihugo.cachix.org"
     ];
     extra-trusted-public-keys = [
       # Community cache keys
       "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
       "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
       # Organization cache key
-      "singularity-ng.cachix.org-1:your-signing-key-here"
+      "mikkihugo.cachix.org-1:your-signing-key-here"
     ];
   };