ci: test self-hosted x86 runners

.github/workflows/nix.yml

@@ -2,7 +2,7 @@ on: [push, pull_request]
 name: Nix
 jobs:
   check-zig-cache-hash:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-sm
     steps:
       - name: Checkout code
         uses: actions/checkout@v4

.github/workflows/test.yml

@@ -5,7 +5,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest]
+        os: ["ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-md"]
 
         target: [
             aarch64-linux,
@@ -41,7 +41,7 @@ jobs:
         run: nix develop -c zig build -Dstatic=true -Dapp-runtime=glfw -Dtarget=${{ matrix.target }}
 
   build-linux-libghostty:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-md
     needs: test
     steps:
       - name: Checkout code
@@ -60,7 +60,7 @@ jobs:
         run: nix develop -c zig build -Dapp-runtime=none
 
   build-nix:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-md
     needs: test
     steps:
       - name: Checkout code
@@ -183,7 +183,7 @@ jobs:
         run: Get-Content -Path ".\build.log"
 
   test:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-md
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -210,7 +210,7 @@ jobs:
         run: nix develop -c zig build -Dstatic=false
 
   prettier:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-sm
     steps:
       - uses: actions/checkout@v4 # Check out repo so we can lint it
       - uses: cachix/install-nix-action@v24
@@ -224,7 +224,7 @@ jobs:
         run: nix develop -c prettier --check .
 
   alejandra:
-    runs-on: ubuntu-latest
+    runs-on: ghcr.io/cirruslabs/ubuntu-runner-amd64:22.04-sm
     steps:
       - uses: actions/checkout@v4 # Check out repo so we can lint it
       - uses: cachix/install-nix-action@v24