Fix test workflow for host mode, add custom runner image plan

- Use git clone instead of actions/checkout (no Node.js in runner)
- Add Use Case 0 to P4: build custom runner image with Node.js

The stock forgejo/runner image lacks Node.js, so standard GitHub
Actions don't work in host mode. P4 now includes building a custom
runner image as the first step.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.forgejo/workflows/test.yaml

@@ -10,7 +10,12 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout (git clone)
+        run: |
+          git clone --depth 1 --branch "${{ gitea.ref_name }}" \
+            "${{ gitea.server_url }}/${{ gitea.repository }}.git" .
+        env:
+          GIT_SSL_NO_VERIFY: "true"
 
       - name: Hello World
         run: |
@@ -18,3 +23,4 @@ jobs:
           echo "Runner: $(hostname)"
           echo "Repository: ${{ gitea.repository }}"
           echo "Branch: ${{ gitea.ref_name }}"
+          ls -la

plans/ci-cd-bootstrap/P4_container_builds.md

@@ -17,6 +17,78 @@ With Forgejo Actions operational, we can now build container images for:
 
 ---
 
+## Use Case 0: Custom Runner Image
+
+### Problem
+
+The stock `forgejo/runner` image lacks tools needed for standard GitHub Actions:
+- **Node.js** - Required by most actions (checkout, setup-*, etc.)
+- **Docker CLI** - For building container images
+- **Git** - For repository operations
+- **Common build tools** - make, gcc, etc.
+
+In host mode, jobs run directly in the runner container, so these tools must be pre-installed.
+
+### Solution
+
+Build a custom runner image with all necessary tools:
+
+```dockerfile
+# argocd/manifests/forgejo-runner/Dockerfile
+FROM code.forgejo.org/forgejo/runner:3.5.1
+
+# Install Node.js (required for most GitHub Actions)
+RUN apt-get update && apt-get install -y \
+    nodejs \
+    npm \
+    git \
+    curl \
+    docker.io \
+    make \
+    gcc \
+    && rm -rf /var/lib/apt/lists/*
+```
+
+### Workflow
+
+Create `.forgejo/workflows/build-runner.yml`:
+
+```yaml
+name: Build Runner Image
+
+on:
+  push:
+    paths:
+      - 'argocd/manifests/forgejo-runner/Dockerfile'
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        run: |
+          git clone --depth 1 "${{ gitea.server_url }}/${{ gitea.repository }}.git" .
+
+      - name: Build and push
+        run: |
+          cd argocd/manifests/forgejo-runner
+          docker build -t registry.tail8d86e.ts.net/blumeops/forgejo-runner:latest .
+          docker push registry.tail8d86e.ts.net/blumeops/forgejo-runner:latest
+```
+
+### Update Deployment
+
+Once the custom image is built, update `argocd/manifests/forgejo-runner/deployment.yaml`:
+
+```yaml
+image: registry.tail8d86e.ts.net/blumeops/forgejo-runner:latest
+```
+
+This enables standard GitHub Actions like `actions/checkout@v4` to work in host mode.
+
+---
+
 ## Use Case 1: devpi Custom Image
 
 ### Current State