feat: add Gitea Actions workflow for Docker builds

Add Gitea Actions workflow to automatically build and push Docker
images to Gitea container registry.

New files:
- .gitea/workflows/build.yaml: Automated Docker build workflow
  - Triggers on push to main, tags, and manual dispatch
  - Builds Docker image from Dockerfile
  - Tags appropriately (commit SHA, tags, latest)
  - Pushes to Gitea registry at 10.0.1.10

- CONTAINER_REGISTRY.md: Complete documentation for:
  - Enabling Gitea container registry
  - Setting up CI/CD with Gitea Actions
  - Creating and using personal access tokens
  - Pulling and pushing images
  - Troubleshooting common issues

The workflow is compatible with the existing Dockerfile and provides
automated builds similar to the GitLab CI pipeline.

Prerequisites:
- Gitea container registry enabled
- GITEA_TOKEN secret configured with write:package scope

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.gitea/workflows/build.yaml

@@ -0,0 +1,77 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - '*'
+  workflow_dispatch:
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Determine image tags
+        id: tags
+        run: |
+          REGISTRY="10.0.1.10"
+          REPO_OWNER="${{ gitea.repository_owner }}"
+          REPO_NAME="${{ gitea.repository }}"
+
+          # Extract repository name without owner
+          REPO_NAME_ONLY=$(echo "$REPO_NAME" | cut -d'/' -f2)
+
+          # Base image path
+          IMAGE_BASE="${REGISTRY}/${REPO_OWNER}/${REPO_NAME_ONLY}"
+
+          # Determine tag based on ref
+          if [[ "${{ gitea.ref }}" == refs/tags/* ]]; then
+            # Tag push - use the tag name
+            TAG_NAME="${{ gitea.ref_name }}"
+            echo "IMAGE_TAG=${IMAGE_BASE}:${TAG_NAME}" >> $GITHUB_OUTPUT
+            echo "PUSH_LATEST=true" >> $GITHUB_OUTPUT
+          elif [[ "${{ gitea.ref_name }}" == "main" ]]; then
+            # Main branch - use commit SHA and latest
+            echo "IMAGE_TAG=${IMAGE_BASE}:${{ gitea.sha_short }}" >> $GITHUB_OUTPUT
+            echo "PUSH_LATEST=true" >> $GITHUB_OUTPUT
+          else
+            # Other branches - use branch name
+            BRANCH_TAG=$(echo "${{ gitea.ref_name }}" | sed 's/\//-/g')
+            echo "IMAGE_TAG=${IMAGE_BASE}:${BRANCH_TAG}" >> $GITHUB_OUTPUT
+            echo "PUSH_LATEST=false" >> $GITHUB_OUTPUT
+          fi
+
+          echo "IMAGE_LATEST=${IMAGE_BASE}:latest" >> $GITHUB_OUTPUT
+
+      - name: Log in to Gitea Container Registry
+        run: |
+          echo "${{ secrets.GITEA_TOKEN }}" | docker login 10.0.1.10 -u "${{ gitea.actor }}" --password-stdin
+
+      - name: Build Docker image
+        run: |
+          echo "Building Docker image..."
+          if [[ "${{ steps.tags.outputs.PUSH_LATEST }}" == "true" ]]; then
+            docker build -t ${{ steps.tags.outputs.IMAGE_TAG }} -t ${{ steps.tags.outputs.IMAGE_LATEST }} .
+          else
+            docker build -t ${{ steps.tags.outputs.IMAGE_TAG }} .
+          fi
+
+      - name: Push Docker image
+        run: |
+          echo "Pushing Docker image to registry..."
+          docker push ${{ steps.tags.outputs.IMAGE_TAG }}
+
+          if [[ "${{ steps.tags.outputs.PUSH_LATEST }}" == "true" ]]; then
+            echo "Pushing latest tag..."
+            docker push ${{ steps.tags.outputs.IMAGE_LATEST }}
+          fi
+
+          echo "Build and push completed successfully!"
+          echo "Image available at ${{ steps.tags.outputs.IMAGE_TAG }}"

CONTAINER_REGISTRY.md

@@ -0,0 +1,188 @@
+# Container Registry and CI/CD Setup
+
+This document explains how to build and push Docker images using Gitea Actions and the Gitea Container Registry.
+
+## Overview
+
+The SPARC project uses Gitea Actions (GitHub Actions-compatible) to automatically build and push Docker images to the Gitea Container Registry whenever code is pushed to the repository.
+
+## Workflow Configuration
+
+The workflow is defined in `.gitea/workflows/build.yaml` and automatically:
+- Builds the Docker image from the `Dockerfile`
+- Tags the image appropriately based on the git ref (branch/tag)
+- Pushes to the Gitea Container Registry at `10.0.1.10`
+
+### Triggers
+
+The workflow runs on:
+- **Push to main branch**: Builds and tags with commit SHA + `latest`
+- **Push of tags**: Builds and tags with the tag name + `latest`
+- **Manual dispatch**: Can be triggered manually from Gitea UI
+
+### Image Naming
+
+Images are pushed to: `10.0.1.10/0xwheatyz/sparc:<tag>`
+
+- Main branch commits: `10.0.1.10/0xwheatyz/sparc:<sha>` and `10.0.1.10/0xwheatyz/sparc:latest`
+- Tags: `10.0.1.10/0xwheatyz/sparc:<tag-name>` and `10.0.1.10/0xwheatyz/sparc:latest`
+- Other branches: `10.0.1.10/0xwheatyz/sparc:<branch-name>`
+
+## Prerequisites
+
+### 1. Enable Container Registry in Gitea
+
+The Gitea instance must have the Container Registry (Packages) feature enabled:
+
+1. Access Gitea as administrator
+2. Go to Site Administration > Configuration
+3. Find "Packages" section
+4. Ensure packages/container registry is enabled
+
+### 2. Create Personal Access Token
+
+The workflow needs a personal access token with package write permissions:
+
+1. In Gitea UI, click your profile → Settings
+2. Go to Applications → Manage Access Tokens
+3. Click "Generate New Token"
+4. Give it a descriptive name (e.g., "Actions Container Registry")
+5. Select scopes:
+   - `write:package` (required)
+   - `read:package` (required)
+6. Click "Generate Token"
+7. **Copy the token immediately** (you won't see it again)
+
+### 3. Add Token as Repository Secret
+
+1. Go to your repository in Gitea
+2. Click Settings → Secrets
+3. Click "Add Secret"
+4. Name: `GITEA_TOKEN`
+5. Value: Paste the personal access token
+6. Click "Add Secret"
+
+## Usage
+
+### Automatic Builds
+
+Once configured, the workflow runs automatically:
+
+```bash
+# Push to main branch - triggers build
+git add .
+git commit -m "feat: add new feature"
+git push origin main
+
+# Create and push a tag - triggers build with tag
+git tag v1.0.0
+git push origin v1.0.0
+```
+
+### Manual Builds
+
+You can also trigger builds manually:
+
+1. Go to repository → Actions
+2. Click on "Build and Push Docker Image" workflow
+3. Click "Run workflow"
+4. Select the branch
+5. Click "Run workflow"
+
+### Monitor Build Progress
+
+1. Go to repository → Actions
+2. Click on the running workflow
+3. View logs for each step
+
+## Pulling Images
+
+Once built, images can be pulled from the registry:
+
+```bash
+# Log in to registry
+docker login 10.0.1.10 -u your-username
+
+# Pull the latest image
+docker pull 10.0.1.10/0xwheatyz/sparc:latest
+
+# Pull a specific tag
+docker pull 10.0.1.10/0xwheatyz/sparc:v1.0.0
+
+# Pull a specific commit
+docker pull 10.0.1.10/0xwheatyz/sparc:abc1234
+```
+
+## Troubleshooting
+
+### Workflow Fails at Login Step
+
+**Error**: `Error response from daemon: login attempt to http://10.0.1.10/v2/ failed with status: 404 Not Found`
+
+**Solution**: Container registry is not enabled in Gitea. Contact administrator to enable packages feature.
+
+### Workflow Fails with 401 Unauthorized
+
+**Error**: `unauthorized: authentication required`
+
+**Solutions**:
+1. Verify `GITEA_TOKEN` secret exists and is correct
+2. Verify token has `write:package` and `read:package` scopes
+3. Regenerate token if it has expired
+
+### Workflow Fails at Push Step
+
+**Error**: `denied: permission denied`
+
+**Solutions**:
+1. Ensure your user account has write access to the repository
+2. Verify the token has the correct permissions
+3. Check if the repository owner matches the registry path
+
+### Image Not Appearing in Packages
+
+**Check**:
+1. Go to repository → Packages tab
+2. If no packages appear, check workflow logs for errors
+3. Verify the image was successfully pushed (check workflow output)
+
+## Advanced Configuration
+
+### Using a Different Registry
+
+To push to a different container registry (e.g., Docker Hub, GHCR):
+
+1. Update the `REGISTRY` variable in `.gitea/workflows/build.yaml`
+2. Update the login step with appropriate credentials
+3. Add registry credentials as secrets
+
+### Building Multi-platform Images
+
+To build for multiple architectures:
+
+```yaml
+- name: Build Docker image
+  run: |
+    docker buildx build \
+      --platform linux/amd64,linux/arm64 \
+      -t ${{ steps.tags.outputs.IMAGE_TAG }} \
+      --push .
+```
+
+### Adding Build Arguments
+
+To pass build arguments:
+
+```yaml
+- name: Build Docker image
+  run: |
+    docker build \
+      --build-arg VERSION=${{ gitea.sha_short }} \
+      -t ${{ steps.tags.outputs.IMAGE_TAG }} .
+```
+
+## References
+
+- [Gitea Actions Documentation](https://docs.gitea.com/usage/actions/overview)
+- [Gitea Packages Documentation](https://docs.gitea.com/usage/packages/overview)
+- [GitHub Actions Syntax](https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions) (Gitea Actions compatible)