fix(ci): replace actions/checkout with manual git clone

The act_runner cannot create /home/act_runner cache dir inside
container images. Replace actions/checkout@v4 with manual
git clone using GITHUB_SERVER_URL and GITHUB_REPOSITORY env vars.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -24,7 +24,10 @@ jobs:
     if: github.event_name == 'pull_request'
     container: golangci/golangci-lint:v1.55-alpine
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apk add --no-cache git
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Lint consent-service
         run: |
           if [ -d "consent-service" ]; then
@@ -36,7 +39,10 @@ jobs:
     if: github.event_name == 'pull_request'
     container: python:3.12-slim
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apt-get update -qq && apt-get install -y -qq git > /dev/null 2>&1
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Lint Python services
         run: |
           pip install --quiet ruff
@@ -52,7 +58,10 @@ jobs:
     if: github.event_name == 'pull_request'
     container: node:20-alpine
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apk add --no-cache git
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Lint admin-core
         run: |
           if [ -d "admin-core" ]; then
@@ -71,11 +80,13 @@ jobs:
     env:
       CGO_ENABLED: "0"
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apk add --no-cache git
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Test consent-service
         run: |
-          apk add --no-cache jq bash
+          if [ ! -d "consent-service" ]; then
-          if [ \! -d "consent-service" ]; then
             echo "WARNUNG: consent-service nicht gefunden"
             exit 0
           fi
@@ -90,10 +101,13 @@ jobs:
     env:
       CI: "true"
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apt-get update -qq && apt-get install -y -qq git > /dev/null 2>&1
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Test voice-service
         run: |
-          if [ \! -d "voice-service" ]; then
+          if [ ! -d "voice-service" ]; then
             echo "WARNUNG: voice-service nicht gefunden"
             exit 0
           fi
@@ -109,10 +123,13 @@ jobs:
     env:
       CI: "true"
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout
+        run: |
+          apt-get update -qq && apt-get install -y -qq git > /dev/null 2>&1
+          git clone --depth 1 --branch ${GITHUB_REF_NAME} ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git .
       - name: Test BQAS
         run: |
-          if [ \! -d "voice-service/tests/bqas" ]; then
+          if [ ! -d "voice-service/tests/bqas" ]; then
             echo "WARNUNG: BQAS Tests nicht gefunden"
             exit 0
           fi