ci: right-size codeql quality runners

Run CodeQL Critical Quality on 4 vCPU Blacksmith runners.

.github/actionlint.yaml

@@ -4,6 +4,7 @@
 self-hosted-runner:
   labels:
     # Blacksmith CI runners
+    - blacksmith-4vcpu-ubuntu-2404
     - blacksmith-8vcpu-ubuntu-2404
     - blacksmith-8vcpu-windows-2025
     - blacksmith-16vcpu-ubuntu-2404

.github/workflows/codeql-critical-quality.yml

@@ -20,7 +20,7 @@ permissions:
 jobs:
   javascript-typescript:
     name: Critical Quality (javascript-typescript)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout
@@ -41,7 +41,7 @@ jobs:
 
   config-boundary:
     name: Critical Quality (config-boundary)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout
@@ -62,7 +62,7 @@ jobs:
 
   gateway-runtime-boundary:
     name: Critical Quality (gateway-runtime-boundary)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout
@@ -83,7 +83,7 @@ jobs:
 
   channel-runtime-boundary:
     name: Critical Quality (channel-runtime-boundary)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout
@@ -104,7 +104,7 @@ jobs:
 
   agent-runtime-boundary:
     name: Critical Quality (agent-runtime-boundary)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout
@@ -125,7 +125,7 @@ jobs:
 
   plugin-boundary:
     name: Critical Quality (plugin-boundary)
-    runs-on: blacksmith-8vcpu-ubuntu-2404
+    runs-on: blacksmith-4vcpu-ubuntu-2404
     timeout-minutes: 25
     steps:
       - name: Checkout