Update GITEA_SETUP.md with optional Docker configuration

- Document Docker installation on runner for image builds
- Clarify that Docker is optional (not required for binary builds)
- Add instructions for running the runner user with Docker permissions
- Update troubleshooting section with Docker-specific guidance
- Explain graceful handling when Docker is not available
- Add Docker installation link in support section

GITEA_SETUP.md

@@ -58,7 +58,7 @@ sudo systemctl restart gitea
 
 ## Setting Up a Runner (if needed)
 
-If you don't have any runners yet, you need to set one up. This can be on the Gitea server itself or any machine with Docker/Go.
+If you don't have any runners yet, you need to set one up. This can be on the Gitea server itself or any machine with Docker and Go.
 
 ### Quick Runner Setup
 
@@ -84,45 +84,25 @@ To get a runner token:
 3. Click **Create new runner**
 4. Follow the registration steps
 
-## Testing the Setup
+### Installing Docker on the Runner (Optional)
 
-Once everything is configured:
+If you want to build Docker images as part of your releases, install Docker on the runner:
 
-1. **Push a test tag**:
 ```bash
-git tag -a v0.0.1-test -m "Test release"
+# Install Docker
-git push origin v0.0.1-test
+curl -fsSL https://get.docker.com -o get-docker.sh
+sudo sh get-docker.sh
+
+# Add permissions for the runner user to use Docker
+sudo usermod -aG docker $USER
+
+# Verify Docker is working
+docker --version
+
+# Note: You may need to logout and login for group permissions to take effect
 ```
 
-2. **Monitor the build**:
+**Without Docker**: The binary builds will still work. Only Docker image generation will be skipped (the workflow will show a warning but still succeed).
-   - Go to Actions tab
-   - You should see the workflow running
-   - Check logs for any errors
-
-3. **Verify the release**:
-   - Go to Releases tab
-   - You should see a new release with binaries and checksums
-
-## Troubleshooting
-
-### "Action not found" error
-- Make sure Gitea Actions is enabled
-- Restart Gitea if you just enabled it: `sudo systemctl restart gitea`
-
-### No runners available
-- Runner must be registered: Administration → Actions → Runners
-- Runner machine must have Docker and Go installed
-- Check if runner is online in the UI
-
-### "GITEA_TOKEN" not found
-- Make sure the secret is named exactly `GITEA_TOKEN` (case-sensitive)
-- Go to Settings → Secrets and verify it's there
-- If it's there, try re-running the workflow
-
-### Build fails with permission denied
-- Make sure the runner has permission to run Docker commands
-- On the runner machine: `sudo usermod -aG docker $USER`
-- Logout and log back in for the group change to take effect
 
 ## What Happens Next
 
@@ -130,22 +110,51 @@ Once you've set everything up:
 
 1. **Every push to main/master** triggers the build job:
    - Compiles all platform binaries
-   - Builds Docker images
+   - Attempts to build Docker images (skips if Docker unavailable)
    - Uploads artifacts as build artifacts
 
 2. **Every git tag push** (e.g., `v1.0.0`) triggers the full release:
    - Does all of the above
    - Creates a Gitea Release
-   - Uploads all binaries and Docker images to the release
+   - Uploads all binaries and checksums to the release
-   - Generates SHA256 checksums
+   - Uploads Docker images if available
 
 3. **Releases are available in**:
    - Repository Releases tab in Gitea
    - Binaries ready for download
-   - Docker images ready for import
+   - Docker images (if Docker is available on runner)
+
+## Troubleshooting
+
+### "docker: command not found" in workflow
+- Docker is not installed on your runner
+- This is **optional** - binaries will still build
+- If you want Docker images, install Docker on the runner (see above)
+- The workflow will gracefully skip Docker builds and show a warning
+
+### "Action not found" error
+- Make sure Gitea Actions is enabled
+- Restart Gitea if you just enabled it: `sudo systemctl restart gitea`
+
+### No runners available
+- Runner must be registered: Administration → Actions → Runners
+- Runner machine must have Go installed (1.24.4 or later)
+- Docker is optional (for building Docker images)
+- Check if runner is online in the UI
+
+### "GITEA_TOKEN" not found
+- Make sure the secret is named exactly `GITEA_TOKEN` (case-sensitive)
+- Go to Settings → Secrets and verify it's there
+- If it's there, try re-running the workflow
+
+### Build fails with permission denied (Docker)
+- Make sure the runner user has permission to run Docker commands
+- On the runner machine: `sudo usermod -aG docker $USER`
+- Logout and log back in for the group change to take effect
 
 ## Support
 
 - Gitea Actions Docs: https://docs.gitea.io/en-us/actions/
 - Act Runner Docs: https://gitea.com/gitea/act_runner
+- Docker Installation: https://docs.docker.com/install/
 - For issues with the workflow itself, check the Actions tab logs