feat(ci): add gitops-update workflow to open image-bump PR in home-kubernetes

After a successful Go image build, uh-cli opens a PR against
kacerr/home-kubernetes that bumps the fuj-management Deployment
(namespace fuj) to the newly published image tag. Supports
workflow_run auto-trigger and workflow_dispatch with dry-run option.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/gitops-update.yaml

@@ -0,0 +1,94 @@
+name: GitOps image update
+
+on:
+  # Auto-fires when "Build and Push" completes successfully (tag push).
+  workflow_run:
+    workflows: ["Build and Push"]
+    types: [completed]
+
+  # Manual trigger for dry-runs and one-off bumps.
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Git tag to deploy (without the -go suffix, e.g. 0.37)"
+        required: true
+      dry_run:
+        description: "Dry run — print diff, do not open a PR"
+        type: boolean
+        default: false
+      uh_cli_version:
+        description: "uh-cli version override (e.g. v0.2.0). Defaults to v0.1.0."
+        required: false
+
+env:
+  TEA_VERSION: "0.9.2"
+  # Resolved priority: manual input → repo/org variable → hardcoded default.
+  UH_CLI_VERSION: ${{ inputs.uh_cli_version || vars.UH_CLI_VERSION || 'v0.1.0' }}
+
+jobs:
+  gitops-pr:
+    runs-on: ubuntu-latest
+    # Skip if triggered by workflow_run that did not succeed.
+    if: >
+      github.event_name == 'workflow_dispatch' ||
+      github.event.workflow_run.conclusion == 'success'
+    container:
+      image: ubuntu:latest
+
+    env:
+      GITEA_TOKEN: ${{ secrets.GITOPS_TOKEN }}
+
+    steps:
+      - name: Install git, curl, ca-certificates
+        run: |
+          apt-get update -qq
+          apt-get install -y --no-install-recommends git curl ca-certificates
+
+      - name: Install tea
+        run: |
+          curl -fsSL \
+            "https://gitea.com/gitea/tea/releases/download/v${TEA_VERSION}/tea-${TEA_VERSION}-linux-amd64" \
+            -o /usr/local/bin/tea
+          chmod +x /usr/local/bin/tea
+
+      - name: Install uh-cli
+        run: |
+          curl -fsSL \
+            "https://gitea.home.hrajfrisbee.cz/kacerr/uh-cli/releases/download/${UH_CLI_VERSION}/uh-cli-${UH_CLI_VERSION}-linux-amd64" \
+            -o /usr/local/bin/uh-cli
+          chmod +x /usr/local/bin/uh-cli
+
+      - name: Resolve image tag
+        id: resolve
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            GIT_TAG="${{ inputs.tag }}"
+          else
+            # workflow_run: use the ref name of the triggering workflow (the pushed git tag).
+            GIT_TAG="${{ github.event.workflow_run.head_branch }}"
+          fi
+          IMAGE="gitea.home.hrajfrisbee.cz/${{ github.repository }}:${GIT_TAG}-go"
+          echo "image=${IMAGE}" >> "$GITHUB_OUTPUT"
+          echo "Resolved image: ${IMAGE}"
+
+      - name: Configure git identity
+        run: |
+          git config --global user.name  "uh-cli bot"
+          git config --global user.email "bot@hrajfrisbee.cz"
+
+      - name: Authenticate tea
+        run: |
+          tea login add \
+            --name     ci \
+            --url      https://gitea.home.hrajfrisbee.cz \
+            --token    "$GITEA_TOKEN"
+
+      - name: Open image-update PR (or dry run)
+        run: |
+          uh-cli -v gitops deployment update \
+            --deployment-name fuj-management \
+            --deployment-namespace fuj \
+            --set-image "${{ steps.resolve.outputs.image }}" \
+            --git-repo "https://kacerr:${GITEA_TOKEN}@gitea.home.hrajfrisbee.cz/kacerr/home-kubernetes" \
+            --git-path gitops/home-kubernetes \
+            ${{ (github.event_name == 'workflow_dispatch' && inputs.dry_run == 'true') && '--dry-run' || '' }}