fix(ci): serialize build+deploy via concurrency group to prevent Docker exhaustion

.gitea/workflows/ci.yaml

@@ -9,6 +9,12 @@ on:
       - main
   workflow_dispatch:
 
+# Same group as deploy-gke so builds and deploys queue behind each other.
+# Prevents concurrent Docker daemon exhaustion on the single GCE runner.
+concurrency:
+  group: neuron-runner
+  cancel-in-progress: false
+
 jobs:
   build:
     runs-on: ubuntu-latest

.gitea/workflows/deploy-gke.yaml

@@ -18,6 +18,12 @@ on:
         required: false
         default: "green"
 
+# Serialize all builds on this runner — concurrent jobs exhaust the Docker daemon.
+# A queued deploy runs after the in-progress build finishes.
+concurrency:
+  group: neuron-runner
+  cancel-in-progress: false
+
 jobs:
   deploy:
     runs-on: ubuntu-latest