Merge branch 'feat/footer-share-ci' into dev

CI keeps the 'test once per code state' plan but records commit and
git tree as image labels instead of extra :sha-/:tree- tags, so the
registry only holds dev, latest, vX.Y.Z and stable; the plan test now
asserts the expected decisions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/scripts/test-build-plan.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Checks build-plan.sh against a fake registry (labels given per case). Usage: .gitea/scripts/test-build-plan.sh
+set -euo pipefail
+cd "$(git rev-parse --show-toplevel)"
+PLAN=.gitea/scripts/build-plan.sh
+IMAGE=registry.example/mindsift
+SHA="$(git rev-parse HEAD)"
+TREE="$(git rev-parse HEAD^{tree})"
+MOCK="$(mktemp)"
+trap 'rm -f "$MOCK"' EXIT
+# The fake registry answers from $DEV_TREE, $LATEST_TREE and $LATEST_SHA
+cat >"$MOCK" <<'EOF'
+#!/usr/bin/env bash
+case "$1 $2" in
+  *:dev\ io.mindsift.tree) echo "${DEV_TREE:-}" ;;
+  *:latest\ io.mindsift.tree) echo "${LATEST_TREE:-}" ;;
+  *:latest\ org.opencontainers.image.revision) echo "${LATEST_SHA:-}" ;;
+esac
+EOF
+chmod +x "$MOCK"
+
+fails=0
+expect() { # name, REF, expected "action skip_tests tags", env assignments…
+  local name="$1" ref="$2" want="$3"
+  shift 3
+  local out
+  out="$(env "$@" REF="$ref" IMAGE="$IMAGE" PKG_VERSION=0.10.0 LABEL_CMD="$MOCK" GITHUB_OUTPUT= "$PLAN")"
+  local got
+  got="$(echo "$out" | sed -n 's/^action=//p') $(echo "$out" | sed -n 's/^skip_tests=//p') $(echo "$out" | sed -n 's/^tags=//p')"
+  if [ "$got" = "$want" ]; then
+    echo "OK   $name: $got"
+  else
+    echo "FEHL $name: erwartet '$want', bekommen '$got'"
+    fails=$((fails + 1))
+  fi
+}
+
+expect "dev baut mit Tests" refs/heads/dev "build 0 dev"
+expect "main nach getestetem dev" refs/heads/main "build 1 latest" DEV_TREE="$TREE"
+expect "main mit anderem Stand" refs/heads/main "build 0 latest" DEV_TREE=0000
+expect "Tag auf latest-Commit" refs/tags/v0.10.0 "retag 1 v0.10.0 stable" LATEST_SHA="$SHA" LATEST_TREE="$TREE"
+expect "Tag, latest fehlt, dev getestet" refs/tags/v0.10.0 "build 1 v0.10.0 stable" DEV_TREE="$TREE"
+expect "Tag auf unbekanntem Stand" refs/tags/v0.10.0 "build 0 v0.10.0 stable"
+expect "Vorabversion ohne stable" refs/tags/v0.11.0-rc.1 "retag 1 v0.11.0-rc.1" LATEST_SHA="$SHA"
+expect "Feature-Branch" refs/heads/feat/x "build 0 feat-x"
+
+if [ "$fails" -gt 0 ]; then
+  echo "$fails FEHLGESCHLAGEN"
+  exit 1
+fi
+echo "ALLE FÄLLE BESTANDEN"