Add agent-executable docs for Konflux setup

Signed-off-by: Daniel Farrell <[email protected]>

Author: dfarrell07

.agents/workflows/konflux-lighthouse-setup.md

@@ -0,0 +1,100 @@
+#### Setting up Lighthouse Builds in Konflux on New Branch
+
+**Prerequisites:**
+
+- Configuration added in konflux-ci/build-definitions repo
+- Existing Konflux-configured branch to copy files from (e.g., `release-0.21`)
+
+**Placeholders:**
+
+- `<target-branch>`: Your target branch (e.g., `release-0.22`)
+- `<X-Y>`: Version with dashes (e.g., `0-22`)
+- `<component>`: Component name (agent or coredns)
+
+**Important:** Lighthouse uses gomod-only prefetch (NO RPM dependencies). Gomod paths differ per component (see Step 3).
+
+**Repeat steps 1-6 for each component (agent, coredns):**
+
+##### 1. Checkout Bot's PR Branch
+
+Bot creates PRs on branches named `konflux-lighthouse-<component>-<X-Y>`.
+
+```bash
+git checkout konflux-lighthouse-<component>-<X-Y>
+```
+
+##### 2. Copy Tekton Configuration from Previous Release
+
+```bash
+TARGET_VERSION=$(echo "<target-branch>" | grep -oP '(?<=release-0\.)\d+$')
+[ -z "$TARGET_VERSION" ] && { echo "ERROR: Invalid branch format"; exit 1; }
+PREV_VERSION=$((TARGET_VERSION - 1))
+
+for type in pull-request push; do
+  git show "origin/release-0.${PREV_VERSION}:.tekton/lighthouse-<component>-0-${PREV_VERSION}-${type}.yaml" | \
+    sed "s/0-${PREV_VERSION}/0-${TARGET_VERSION}/g; s/release-0\.${PREV_VERSION}/release-0.${TARGET_VERSION}/g" \
+    > ".tekton/lighthouse-<component>-0-${TARGET_VERSION}-${type}.yaml"
+done
+```
+
+**Note:** Extracts YAML from previous release and updates versions in one step. Avoids intermediate files and sed parameter insertion bugs.
+
+##### 3. Update Gomod Prefetch Paths
+
+**For lighthouse-agent:**
+
+```bash
+sed -i 's|\[{"type": "gomod", "path": "."}, {"type": "gomod", "path": "coredns"}, {"type": "gomod", "path": "tools"}]|[{"type": "gomod", "path": "."}, {"type": "gomod", "path": "tools"}]|' .tekton/lighthouse-agent-0-${TARGET_VERSION}-*.yaml
+```
+
+**For lighthouse-coredns:**
+
+```bash
+sed -i 's|\[{"type": "gomod", "path": "."}, {"type": "gomod", "path": "coredns"}, {"type": "gomod", "path": "tools"}]|[{"type": "gomod", "path": "./coredns"}]|' .tekton/lighthouse-coredns-0-${TARGET_VERSION}-*.yaml
+```
+
+**Note:** Agent uses root+tools modules, coredns uses only coredns module.
+
+##### 4. Add Konflux Dockerfile
+
+```bash
+git checkout origin/release-0.${PREV_VERSION} -- package/Dockerfile.lighthouse-<component>.konflux
+sed -i "s/release-0.${PREV_VERSION}/release-0.${TARGET_VERSION}/g" package/Dockerfile.lighthouse-<component>.konflux
+```
+
+**Note:** Lighthouse Dockerfiles have no CPE labels (only BASE_BRANCH update needed).
+
+##### 5. Commit Changes
+
+```bash
+git add .tekton/lighthouse-<component>-0-${TARGET_VERSION}-*.yaml package/Dockerfile.lighthouse-<component>.konflux
+git commit -s -m "Add Konflux config for lighthouse-<component>"
+```
+
+##### 6. Review and Push
+
+```bash
+git log origin/<target-branch>..HEAD
+git status
+git push origin konflux-lighthouse-<component>-<X-Y> --force-with-lease
+```
+
+Expected: 1 commit (bot's initial + your configuration), clean working tree.
+
+##### 7. Verify All Component PRs
+
+After completing both components:
+
+```bash
+for component in agent coredns; do
+  gh pr list --head konflux-lighthouse-$component-<X-Y>
+done
+```
+
+Expected: 2 PRs (one per component).
+
+**Troubleshooting:**
+
+- **Validation error "impossible ParamValues.Type"**: Step 3 sed pattern mismatch. Check release-0.21's prefetch-input value matches expected format. If different, update Step 3 sed pattern.
+- **Commit message too long**: Use exactly "Add Konflux config for lighthouse-<component>" (40-43 chars).
+- **RPM lockfiles**: Lighthouse has NO RPM dependencies. Do not create `.rpm-lockfiles` directory.