fix(docker): use absolute URL for replace-build-vars action ref

Step-level 'uses:' resolves non-fully-qualified action refs against
github.com by default, unlike job-level reusable-workflow 'uses:' which
resolves against the local Gitea instance. Verified via a live CI run
that the shorthand form failed with "authentication required:
Repository not found" trying to clone from github.com/UltimateCoder/...

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01VVTCJvvJmS4fCSrm5wxwVo

.gitea/workflows/docker.yaml

@@ -43,6 +43,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Replace build placeholders
+        uses: https://git.custom-coding.net/UltimateCoder/resuable-workflows/actions/replace-build-vars@v3
+
       - name: Build Image
         run: |
           docker build \
@@ -59,16 +62,23 @@ jobs:
       - name: Docker Release - Dev
         if: startsWith(github.ref, 'refs/heads/develop') || startsWith(github.ref, 'refs/heads/feature/')
         run: |
-          docker image tag "$IMAGE:latest" "$IMAGE:${GITHUB_REF_NAME}"
+          TAG="${GITHUB_REF_NAME//\//-}"
+          docker image tag "$IMAGE:latest" "$IMAGE:${TAG}"
 
       - name: Docker Release - Tagged
         if: startsWith(github.ref, 'refs/tags/')
         run: |
           docker image tag "$IMAGE:latest" "$IMAGE:${GITHUB_REF_NAME}"
 
+      - name: Docker Release - PR
+        if: startsWith(github.ref, 'refs/pull/')
+        run: |
+          PR_NUM=${GITHUB_REF#refs/pull/}
+          PR_NUM=${PR_NUM%/head}
+          docker image tag "$IMAGE:latest" "$IMAGE:pr-${PR_NUM}"
 
       - name: Docker Push
-        if: startsWith(github.ref, 'refs/heads/master') || startsWith(github.ref, 'refs/heads/develop') || startsWith(github.ref, 'refs/heads/feature/') || startsWith(github.ref, 'refs/tags/')
+        if: startsWith(github.ref, 'refs/heads/master') || startsWith(github.ref, 'refs/heads/develop') || startsWith(github.ref, 'refs/heads/feature/') || startsWith(github.ref, 'refs/tags/') || startsWith(github.ref, 'refs/pull/')
         env:
           USERNAME: ${{ secrets.DockerUsername }}
           PASSWORD: ${{ secrets.DockerPassword }}

actions/replace-build-vars/action.yml

@@ -0,0 +1,42 @@
+name: Replace Build Placeholders
+description: >
+  Ersetzt {{BUILD_VAR_*}}-Platzhalter in allen Textdateien durch Gitea-Actions-Build-Infos
+  (Commit, Branch, Run-Metadaten, …). Sprachunabhängig (reiner Text-Replace,
+  kein Build-Tool-Bezug), kein Input nötig.
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: |
+        set -euo pipefail
+
+        SHA_SHORT="${GITHUB_SHA:0:7}"
+        BUILD_DATE="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
+
+        declare -A VARS=(
+          [BUILD_VAR_GITHUB_SHA]="${GITHUB_SHA:-}"
+          [BUILD_VAR_GITHUB_REF_NAME]="${GITHUB_REF_NAME:-}"
+          [BUILD_VAR_GITHUB_REF_TYPE]="${GITHUB_REF_TYPE:-}"
+          [BUILD_VAR_GITHUB_REPOSITORY]="${GITHUB_REPOSITORY:-}"
+          [BUILD_VAR_GITHUB_REPOSITORY_OWNER]="${GITHUB_REPOSITORY_OWNER:-}"
+          [BUILD_VAR_GITHUB_RUN_ID]="${GITHUB_RUN_ID:-}"
+          [BUILD_VAR_GITHUB_RUN_NUMBER]="${GITHUB_RUN_NUMBER:-}"
+          [BUILD_VAR_GITHUB_RUN_ATTEMPT]="${GITHUB_RUN_ATTEMPT:-}"
+          [BUILD_VAR_GITHUB_RETENTION_DAYS]="${GITHUB_RETENTION_DAYS:-}"
+          [BUILD_VAR_GITHUB_SERVER_URL]="${GITHUB_SERVER_URL:-}"
+          [BUILD_VAR_GITHUB_EVENT_NAME]="${GITHUB_EVENT_NAME:-}"
+          [BUILD_VAR_GITHUB_BASE_REF]="${GITHUB_BASE_REF:-}"
+          [BUILD_VAR_GITHUB_HEAD_REF]="${GITHUB_HEAD_REF:-}"
+          [BUILD_VAR_GITHUB_ACTION_REF]="${GITHUB_ACTION_REF:-}"
+          [BUILD_VAR_GITHUB_ACTION_REPOSITORY]="${GITHUB_ACTION_REPOSITORY:-}"
+          [BUILD_VAR_GITEA_ACTIONS_RUNNER_VERSION]="${GITEA_ACTIONS_RUNNER_VERSION:-}"
+          [BUILD_VAR_COMMIT_SHA_SHORT]="$SHA_SHORT"
+          [BUILD_VAR_BUILD_DATE]="$BUILD_DATE"
+        )
+
+        SED_ARGS=()
+        for key in "${!VARS[@]}"; do
+          SED_ARGS+=(-e "s|{{${key}}}|${VARS[$key]}|g")
+        done
+
+        grep -rIl --exclude-dir=.git '' . | xargs -r sed -i "${SED_ARGS[@]}"